Help regulating pH, KH, & GH

[fl4ian]

I have a moderately (heading toward heavily) planted 100g aquarium. I have some corkscrew val, wisteria, glossostigma, and java moss. I have moderately light bio-load. I am not running any type of CO2. However, I am running two Marineland Penguin 350's (HOB filters) and I have heard that they are actually probably putting CO2 INTO the water (as opposed to off-gassing it). I have several bags of Flourite in the aquarium, I have Matrix in some mesh bags in the spare area in each filter. I use Flourish, Clarity, Stability, & Prime as appropriate.

I have tap water that is:
Ammonia: 0
Nitrite: 0
Nitrate: 8
GH: 9 degrees
KH: 1 degree
pH: 7.1

My tank water continues to drop in pH (apparently because of the lack of KH - and maybe in conjunction with the "over-filtering" - please correct me if I'm wrong). I tried to increase the KH by adding baking soda, however around a third of the amount that I calculated it would take, ended up raising my KH by only 2 degrees, and shot my pH from 6.2 to around 7.5.

My goal is to have a pH around 6.8 - 7.0, with about 6 degrees of KH and GH. I think that at those values the water parameters would be fairly stable. Are these values reasonable and achievable?

I've heard crushed coral might do the trick, however, now I've found Neutral Regulator and Alkaline & Acid Buffers. I'm not sure what to do at this point. I'm looking for minimal effort and low cost solution.

Please give me your guidance.

[Tech Support JS]

fl4ian,

Thanks for contacting us. First off, since you have a planted aquarium, you will want to stick to carbonate based buffers (Acid and Alkaline Buffer) and stay away from phosphate based buffers (Neutral Regulator, Acid and Alkaline Regulator, etc).

Secondly, crushed coral is made up primarily of calcium carbonate. What the theory behind this is that the CaCO3 will dissolve and give you a carbonate source to buffer your pH. Unfortunately, Calcium carbonate is generally insoluble at a pH above 6.5, thus would not be very useful to an aquarium with a pH of around 7.0. You might as well just have rocks down there at that point.

I'm not sure about your Penguins putting CO2 into the water, but the logistics of that doesn't seem like it would make sense. The impact of the return water would indeed increase the amount of CO2 dissolved, but that would then increase the amount of CO2 that dissipates (there is a detailed explanation of chemical laws, but just trust me). Regardless, the amount of CO2 added would not effect your pH too much, only slightly (at the level that would be dissolved form the return) so I would probably put that out of your mind for now.

Your numbers are very reasonable to achieve, and the best way to do that would be to use the Acid and Alkaline Buffers in conjunction at the specific ratios listed on the bottles (remember the ratios are for dosages, not direct ratios.. i.e. it would be one dose of Acid to 2 doses of Alkaline). You will have to give it some time to establish a buffer system, so be patient. In water changes, be sure to add the buffer at the ratios (only for the water change volume) before you add it to your tank, that way you are adding buffered water. I hope this helps, and let us know if you have any other questions, we'll be happy to help!

[fl4ian]

Thanks for the quick response and the insight on the Penguins and the crushed coral. Let me ask a few follow-up questions:

1) once I achieve a stable pH and stable KH, how long will they reasonably stay that way? I mean, at first I will be adding daily to achieve the correct balance. How many weeks of daily dosing should I anticipate (in ordering product) before I achieve some stability? You mentioned that I would need to be patient and give it some time to establish the buffer system - how long do you think is a fair amount of time to assume here. And after it becomes stable, then obviously I wouldn't be dosing daily anymore. Would it be weekly, bi-monthly, monthly? I realize that's probably a difficult question to answer as there are so many variables...

2) would it be advantageous to reduce the GH prior to trying to stabilize the pH and KH? I've seen products like API's water softener pillow that are supposed to drop the GH. Ideally, I'd like the bulk of the GH to come from the KH. KH because I need it (KH) in sufficient quantity to keep the pH stable, and other than that, I'd like to have as soft as water as I can - so I'm thinking about trying one of those pillows to remove the bulk of the GH. Then, as the KH comes up as the buffer, the GH will be much more closely matched to the KH. Is my logic sound here? Does this seem reasonable (to try to remove a fair amount of GH prior to stabilizing? Do you have any experience with water softening pillows? Are there any other methods for removing excess GH?

3) Beside using RO or DI or distilled water, all of which would need to be purchased, is there a better way to condition the tap water to remove the GH prior to putting it in the tank to account for evaporation (or during partial water changes for that matter [in which case, I'd add the buffers also])?

Thanks again for the insight.

[Tech Support JS]

I'll be happy to answer your questions:

1) Every question you asked in the first paragraph is going to be something that varies greatly on a tank-to-tank basis. The length of time it takes to establish a buffer system will depend on the details of your water contents, but in general should not take excessively long. A buffer works to help prevent changes in pH, but that doesnt mean that, say, a great addition of acid to a buffered solution wouldn't lower the pH very quickly. Say I have buffering capacity "X" for one tank with a small bioload. Over time, the pH will change because of the constant acid produced from the organisms. If I have the same buffering capacity "X" with a greater bioload, the pH will shift faster, so you dosing regime will depend on that (in addition to your water chemistry)

2) GH wont typically play too big of a role in pH issues. To some extent, if you have an extremely high GH, it could effect your buffering capacity somewhat. Some of our products have a side effect of softening the water, but none are what you would want to use for your tank. So you may want to investigate on your own about that... I personally use RO water and have never needed to soften water. If you prefer lower hardness in your water, that there is nothing wrong with that, but it wont necessarily help you out too much in your pH issues.

Its important to note that GH and KH are completely separate entities. KH is a measure of your carbonate hardness and measures the amount of carbonates (both bicarbonate and carbonate) someone has in their tank. GH mainly measures the mineral content (magnesium, calcium, potassium). So it is impossible for any of your GH to come from your KH, or vice versa. Its also important to note that KH is not a definite measure of your buffering capacity; again it only measures the amount of carbonates in your tank (which are, in fact, good buffers, and thats why people equate it with buffering capacity). Carbonates and bicarbonates typically want to keep your pH fairly high because they have high pKs, which is the measure of the dissociation constant and can explain why such a little amount of bicarb boosted your pH and not your KH. So re-evaluating your numbers, at a pH of 7-ish you may not be able to achieve a KH as high as 6, but dont worry, its just chemistry. Your water will still be well buffered.

3) To condition the water I would suggest using Prime, which has a beneficial side effect of removing heavy metals. To soften the water you can use whichever method you choose (from above). Definitely add the buffers to the replacement water before you add it to the main water

I hope this information is useful to you and have a great day!

[fl4ian]

I did not know that GH and KH are NOT related. I thought that GH was a total hardness value that included the KH values. In other words, I thought if I had a KH of 1 and a GH of 9, and I added 5 degrees of KH, it would mean that the GH would AUTOMATICALLY go to at least 14, which I specifically don't want to do. What you are saying is the opposite of this, which is great to know.

If I get my KH from 1 to say 5 (assuming a pH of 7.1 and GH of 9):
1) would the pH remain relatively stable?
2) what increase should I expect to see in the GH if any (by raising my KH from 1 to 5)?
3) do pH and KH reach some sort of equilibrium in nature? in other words, everything else equal, if the KH is 9 the pH will be 8.2 or if the KH is 3 then the pH will be 6.2 or something like that? that is what I was getting at when I asked if pH 7-ish and KH 6-ish was reasonable... I don't know what to shoot for realistically.
4) at what KH is water considered to be adequately buffered? what would be a KH value that would be considered to be not adequately buffered?
5) does anything use up the GH? I know that KH is used up to buffer the acids produced by nitrification, etc., but is there a normal process that consumes GH? or does it just continue to accumulate?
6) also, is it true that in order to test tap water properly, it must sit for 24 hours (or sometimes I hear that it needs to be aerated for 24 hrs) prior to testing?
7) what is the difference between baking soda and the Alkaline Buffer? would the alkaline buffer (or baking soda + wonder shells) increase the GH?

[Tech Support JS]

I'm glad to help!

1) This would be a good indication that your pH will be stable.
2) You shouldn't see an increase in GH.
3) You cant really have a set ratio or anything like that. I'll try to keep it short: There is Carbonates and Bicarbonates have a certain pKa, to which they will want to keep the pH at (which are higher than you want it to be). So no matter how much you add, that only means that you will be getting closer and closer to that number. So if you have a higher amount, the stronger they are going to pull.

Imagine your carb/bicarb buffer system as workers on a roof hoisting up a piano (the 'height' of which would be your pH) against gravity (which would be the acids trying to lower your pH). The more guys you have pulling, the higher up the piano will go, and if you have enough, they will lift it all the way up to them, but not higher. If you only have a few guys, your "piano" will not raise up too high, but the few guys trying to pull it up will keep it at a steady height instead of allowing it to fall (since they aren't strong enough to raise it).

4) That would depend on the tank parameters and what pH you want. But generally anywhere between 2-6.

5) Plants can use up the ions that make up your GH, but would probably do so at such a slow rate that you wouldn't notice.

Again, I hope this helps and thanks for posting!

[fl4ian]

sorry for all the questions - the more i find out, the more questions I have - thanks for your patience in educating me. Thanks especially for the analogy of the piano lifters...

I had two more questions in my last reply that you didn't address (#6 & #7), I may have edited too late for you to get those - I'm not sure. But I would like your insight on those. In number 6 I'm referring to testing tap water for pH, KH, GH, ammonia, nitrites, & nitrates.

The only other question at this point would relate to (and be a clarification of) #4 in my last reply - at my target pH level of 6.8-7.0 range (give or take), where in the 2-6 KH range would I ideally be shooting for? 4? 5+? At what point does KH become unhelpful, dangerous, or bad in my pH range?

[Tech Support JS]

Sorry I missed those two at the end, I guess the edit didn't refresh in time...

6) You may want to let your tap water sit for 24 hours to allow everything to equilibrate with the atmosphere, you would probably get better results.

7) Baking soda is sodium bicarbonate, Alkaline Buffer is a proprietary blend of bicarbonate salts as well, and at a much higher quality percentage than typical baking soda. Alkaline Buffer will not raise your GH, only your KH.

*4) (revisited) Because KH, while a good indicator of buffering capacity, is a measure of your carbonates, and not a measure of your buffering capacity as a whole, this number will vary. An exceedingly high KH (8,10,12) will cause ionic imbalance, while a low one (0.5, 1), in your case, would probably indicate inadequate buffering. Your KH will prob. be on the low end, ~2.

Thanks for the post and have a great weekend!

[ForexWop]

Hi, cool post. I have been wondering about this topic,so thanks for writing.

[Tech Support AN]

You are very welcome! That is why we are here and let us know if you have any questions we can help out with! :)

[Cardinals]

Here's another way to look at the pH/KH relationship:
GH is a measure of primarily Calcium and Magnesuim which is unrelated to pH or KH in themselves.
KH is more correctly called 'total alkalinity' and is independant of GH.
KH is easily increased with the addition of bicarbonate based alkalis including sodium bicarbonate (baking soda ) and Seachem's "alkaline buffer" (sodium/potassium +/- other undisclosed bicarbonates, not calcium or magnesium).
There is a fixed relationship between total alkalinity and pH and CO2.
CO2 in the air is around 390ppm (and rising!). CO2 in freshwater aquaria is fairly constant generally only ~0.5 -3ppm. Good water turnover with pumps and aerators will reduce CO2 to the lower end of this range as the gas is released into the atmosphere at the air/water interface (surface).
For the planted aquarium, without supplemental CO2 or phosphate buffers, as KH (total alkalinity) rises, pH rises. As an example in a typical planted aquarium with a CO2 ~ 2 ppm:
pH 7.2 = dKH 1.0
pH 7.4 = dKH 2.0
pH 7.6 = dKH 2.5
pH 7.8 = dKH 4.0
pH 8.0 = dKH 6.0
pH 8.2 = dKH 10.0
pH 8.4 = dKH 25.0
As predicted, this is generally consistent with your observations. (tapwater pH 7.1, dKH1 ).
If you wanted a pH of 7.8, add sodium bicarbonate (i.e. unadulterated baking soda) or Seachem's alkali buffer daily at recommended doses until you have a KH of 3.0. Your pH will be ~7.8.
pH/KH/CO2 tables are readily available on the internet, have a look at the "CO2 table" at tropica.com or http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm.
You can not have a tank with a pH of 7.0 and dKH 6.0 without supplemental CO2.
However, you can add small doses of bicarbonate to neutralise some of the acids continually being produced in your aquarium and keep the pH above 7.0. You will not have much KH at this pH. The system is still stable in practical terms though.

A note regarding the use of the word buffering:
It can be seen that at dKH 10, pH 8.2 it requires a large increase (+15.0dKH) or decrease (-4.0 dKH) in alkalinity to change pH by only 0.2 units. This is where a bicarbonate based buffering system is most powerful in a planted tank. As can also be seen, the system does not have much buffering capacity at pH ~ 7.8 or less.

[Tech Support LK]

Thanks for the reiteration of the information JS supplied back in March :)

CO2 in freshwater aquaria is fairly constant generally only ~0.5 -3ppm.

Can you please reference where you got this information? I have been having difficulty finding factual info on the average amount of CO2 dissolved in FW. Any help would be appreciated.

the planted aquarium, without supplemental CO2 or phosphate buffers, as KH (total alkalinity) rises, pH rises. As an example in a typical planted aquarium with a CO2 ~ 2 ppm:
pH 7.2 = dKH 1.0
pH 7.4 = dKH 2.0
pH 7.6 = dKH 2.5
pH 7.8 = dKH 3.0
pH 8.0 = dKH 6.0
pH 8.2 = dKH 10.0
pH 8.4 = dKH 25.0
As predicted, this is generally consistent with your observations. (tapwater pH 7.1, dKH1 ).
If you wanted a pH of 7.8, add sodium bicarbonate (i.e. unadulterated baking soda) or Seachem's alkali buffer daily at recommended doses until you have a KH of 3.0. Your pH will be ~7.8.



Why are your using 2ppm of CO2 as an average number when the very reference you linked us to says that typical level in planted aquarium is 3-4ppm? Also, based on your chart references I think your calculations are a little off in the above table you created. If I plug in 2ppm CO2 and 3.0dKH, I come up with a pH of about 7.653. Am I missing something?
Thanks!

[Cardinals]

Dear LK
You could do the same chart with CO2 4ppm, it is not the point. The point is that with a fixed CO2 (in equillibrium) KH and pH are positively correlated. As KH rises, so does pH, until pH approaches pKa (my guess ~8.2), and true bicarbonate buffering comes into effect.
Perhaps it would be worthwhile going through the thread again with an open mind? My post was not a reiteration. Some questions to highlight the issues about Seachem referring to these products as "buffers" for acidic pHs:
1) This customer was targeting pH 6.8-7.0, why did her pH rise from 6.2 to 7.5 on addtion of Seachems "buffers"?.
2) If the customer follows Tech Support JS's recommendations for a dKH ~2, what will the pH be?
2) What "buffer" is in the water at pH 6.5?
3) If you had a tank with pH 6.5 KH 0ppm, no supplemental CO2, no other buffers, and you added 1 dose Seachem acid buffer and 1.3 doses Seachem Alkaline Buffer, what would be your pH? What would be your KH? Why?
4) Another way is, for a given CO2, how can you raise the alkalinity with a bicarbonate, but keep the pH at 6.5?
5) Is the product at pH 6.5 a buffer or a pH up/down product? Why?

Does anyone at Seachem have a tank with pH 6.5 and "buffered" with Seachems buffers? If so, what is their KH?

Thank you pointing out the chart error which I have changed to KH 4.0. at pH 7.8.

[Tech Support LK]

Thanks for the questions. I have tried to answer them to the best of my ability below:

1) This customer was targeting pH 6.8-7.0, why did her pH rise from 6.2 to 7.5 on addtion of Seachems "buffers"?.

Customer was using baking soda when this occurred. Not Acid and Alkaline Buffer.

2) If the customer follows Tech Support JS's recommendations for a dKH ~2, what will the pH be?

Well now, that will be dependent upon many variables, such as CO2 concentration and most importantly organic acid load and production.

2) What "buffer" is in the water at pH 6.5?

At a pH of 6.5, assuming a bicarbonate-based buffer, there will be an almost equal mixture of bicarbonate and carbonic acid.

3) If you had a tank with pH 6.5 KH 0ppm, no supplemental CO2, no other buffers, and you added 1 dose Seachem acid buffer and 1.3 doses Seachem Alkaline Buffer, what would be your pH? What would be your KH? Why?

Assuming an inevitable quantity of some CO2 in the water but no CO2 injection, the pH would be 6.5 and the KH would be about 0.5 dKH.


4) Another way is, for a given CO2, how can you raise the alkalinity with a bicarbonate, but keep the pH at 6.5?

Add an acid along with the bicarb.

5) Is the product at pH 6.5 a buffer or a pH up/down product? Why?

It’s a buffer. It buffers the water and resists changes in pH upon the addition of acids.

Does anyone at Seachem have a tank with pH 6.5 and "buffered" with Seachems buffers? If so, what is their KH?


The planted tanks here use tap water for the most part. No need to buffer it and it comes out a pretty good pH for the plants. We do have a couple of tanks using RO/DI water that are buffered using only Alkaline Buffer. pH is below 7. Not sure what the dKH is. To be honest, we perform frequent enough water changes that buffering does not seem as necessary for our situation.

Thank you pointing out the chart error which I have changed to KH 4.0. at pH 7.8.

You’re welcome.

[Cardinals]

Well, if water with a KH of ~0.5 or ~9ppm HCO3- is "buffered" we should start rewriting the chemistry books!
But seriously, why don't you prove me wrong, and Seachem right, grab one of your tanks, (remove all phosphates with phosgen, an excellent product btw) and add 1.3 doses Alkaline Buffer and 1 dose acid buffer. Measure pH/KH daily and let me know the results?


An exceedingly high KH (8,10,12) will cause ionic imbalance, while a low one (0.5, 1), in your case, would probably indicate inadequate buffering. Your KH will prob. be on the low end, ~2...

[pamdaly]

This is my first post and I hope I am correct in posting a reply in this thread versus starting a new one. My questions also have to do with the pH, KH, and GH relationships. I am most appreciative of all I've learned from your postings.

Here's my situation:
29 gal freshwater community tank with mod. to heavy planting. 17 fish are:
5 Cherry Barbs
4 Red Phantom Tetras
5 Blue Harlequins
2 Blue Rams
1 small Pleco

Lots of driftwood, a sponge filter and mechanical filter with carbon pouch, temp kept at about 80 d.
Ammonia 0
Nitrite 0
Nitrate 5
KH 13
GH 11
pH 8.2
water source: East Nebraska deep well - known to be "hard" water (Phosphate: 0) I change out about 4 gal. of water once a week and use Prime at that time. One of my original 3 Blue Rams died - cause unknown but possibly protozoa - treated in hospital tank for one week with Metronidazole but died. Remaining fish active, eating and colorful.

For two months, I have been trying to get my pH down. Actually, I have decreased it from 8.8 to 8.0 - 8.2 but would like to get down to 7.0 - 7.4. I've used acid buffer (1/4 t every day for 2 weeks and lots of driftwood). I've avoided using any other pH down chems knowing my KH and GH are so high and not wanting bounce. I want to get the pH down GRADUALLY and as naturally as possible. I have ordered some peat to put in the filter but believe it may be too gradual or not really effective given hardness measures.

Having recently tested the KH and GH, I'm aware I have a big problem here and want to proceed very carefully. My store expert finally recommended I try mixing RO water with my well water for my weekly changes. I bought 10 gal of RO and am currently just aerating it. If I did this, I would be putting 2 gal of well water and 2 gal of RO in the tank each week. My questions are:
1. Would this eventually bring down the pH?
2. Would it bring it down safely? That is, no huge bounce at some point.
3. Would the high mineral content of my well water preclude the necessity of adding something like Seachem Equilibrium? Would the addition of this product hurt anything even if it's not entirely necessary?
4. Should I continue to use the Acid Buffer while using the RO water in weekly changes?
5. Should I go ahead and use the peat while doing the above?

Finally, I've converted my hospital tank to what I call my "Experimental Tank." If you don't feel comfortable saying with certainty that the above plan using RO is safe and gradual, I could make controlled additions (with measurements after each) using the Exp. Tank. It is 10 gal. and I currently have it set up to establish baseline measurements: it contains 5 gal. of well water with a mechanical filter going. This morning its measurements were :
KH 15 (2 drops more than the main tank)
GH 11 (same as main tank)
pH 8.4 (.2 higher than main tank)

Expert advice from anyone in this thread will be most welcome.

[LabTest57]

1) You should know that well water can contain a lot of protozoa, parasites, depending on local and/or state sewage management (water containing trace amounts of human feces can get into contact with a well if it doesn't meet certain standards - you can google this.) Before I add well water to an aquarium, I treat it with chlorine (at ~4 ppm) for at least 3 hours, then I dechlorinate the water.
2) If your going to lower your PH, lower it slowly everyday (you can cause pH shock to your fish).

3) Your GH seems to be fine, however, your kH should be in the 4 to 6.5 range. The best way to accomplish this instead of using RO water, is lower the pH of the water you add to your aquarium (when making a water change,etc.) to the desired range and let it sit for about a day. In your case, I would get a tank that is close to 30 gal or maybe half of it, and do the water change (pH lowering) method mentioned above; in other words, you can do a 25% water change every other day with water at a lower pH until you get to the desired pH range for your community tank.

[LabTest57]

Some specific amounts of sulfuric acid or pH Down (sulfuric acid), in most cases its dry acid a.k.a sulfuric acid. I use muriatic, but at way lower quantatities (drops) =).
__________________________________________________ ________________________________
For every 5 gallons of water, and assuming your Kh is ~300 ppm and Gh ~260 ppm from a max. flux effect, I would say you can add ~0.05 ounces of sulfuric acid to get your pH in the 7.0 to 7.8 range; however, 7.0 to 7.2 will temporarily show up on test kits until the water is settled or agitated for about a day.

On a 29 gal. tank, to lower the pH dramatically and temporarily to 7.0, add 0.3 ounces of sulfuric acid or pH down. Since you have a large amount of fish for such a small tank, the temp. effect could last for a few days (3-4), and for a mod. to heavily planted tank you can expect your pH to rise (IF your plants are FLOURISHING and not dying). The rise in pH can be slow though.

For "drop measurements" of pH Down or sulfuric acid: add 180 drops for every 30 gallons of water, or 30 drops per 5 gallons of water (assuming your still using well water with a kH of 13 and GH of 11 and pH of 8.0 to 8.4).

[LabTest57]

For every 5 gallons of water, and assuming your Kh is ~300 ppm and Gh ~260 ppm from a max.


Correction: I thought you had 15 kH, for 13 kH it would be ~0.035 ounces per 5 gallons of water.

For drop measurements its 21 drops per 5 gal. of your well water.

Note: you can test and lower the pH anyway you want, to gradually acclimate your fish to the target pH of 7.0 (or range of 7.0 to 7.4). I'm merely giving you some instructions on lowering the pH via acids. =)

[pamdaly]

Dear LabTest57,

Thank you for taking the time to share your knowledge with me.

A few more questions:

1. How gradually should one decrease the pH? I'm in no hurry and don't want to stress the fish. .2 degrees a week?

2. I had avoided using chemicals to decrease the pH because I was afraid of pH bounce. If I take your route, is there a possibility of this and should I use buffers to avoid it?

3. What pH down product would you recommend?

4. You dismissed the RO route. Is this because you don't think it will work or that it is too much work/expense/ or what? My thinking was that its purity when combined half and half with my well water would have benefits in addition to bringing down the pH: e.g. lower the GH. I do have 10 gallons of it sitting beside my tank that I was thinking of using in my 10 gal experimental tank.

Again, thanks for taking an interest.

[LabTest57]

You can do a 16.6% water change everyday with RO water (pH at 7.0), if your kH is at at least 7 and pH at 8.2. However, in your case, your kH will drop -1 to -1.5 every 16% water change with RO water, and pH should drop temporarily -0.2 degrees until your reach about 6 degrees kH to notice some stabe results. Then, your pH should start moving downwards with more stability. If your kH drops too much (i.e. below 2 kH), you will notice instability again.

so whats about 16.6% of 29 gallons, it's about 4.5 gallons.

You should do a 4.5 gallon water change using RO water everyday until you get to your target pH and/or kH. Afterwards, mix some RO water with your source water to get the right combination of kH and pH in order to buffer your tank, so its' kH won't drop any furthur and pH would not fluctuate as much.


Instead of using well water, you can buffer the RO water with seachem alkaline buffers. Hope this helps a bit. =)

[LabTest57]

Forgot to metnion one thing. Having proper gH levels is required for pH stability as well. Keeping gH at least 1 or 2 degrees higher than kH is a must. Target gH should be in the 4 to 8 degree range for your type of fish.

[pamdaly]

I just tested 4 different proportions of well water with RO water. The tests came out like this:

For 1 gal well water with 1/2 gal RO:
pH 7.6
KH 14
GH 7-8

For 1 gal well with 1 gal RO:
pH 7.6
KH 9
GH 6-7

For 1 gal well with 1 and 1/2 gal RO
pH 7.6
KH 7
GH 4-5

For 1 gal well with 2 gal RO
pH 7.6
KH 5-6
GH 4-5

Questions:
1. Why didn't the pH go down as the KH decreased? Does the water have to sit for awhile?
2. You said it was important to keep the GH 1 to 2 degrees "higher" than the KH. It is always lower.
3. Am I correct in concluding that the eventual proportion of well to RO water in my tank should be 1:2? Does this provide enough minerals without adding Equilibrium?
4. If my KH is 5-6, why would I need an alkaline buffer?

You have been most kind in giving your time to my problem.

[LabTest57]

Your GH will be lower because it starts initially lower. If you want your pH lower, use use less well water. Instead of 1 gal for each test, use 1/2 gal. You should notice a difference.

I'm not going by the books in my calculations, I'm just making pure assumptions from intermediate math formulas. If your intial pH is 8.2, you would want to get down one pH level or to 7.2 easy by adding 3 gallons of RO water. A 1:1 ratio should equal to a pH of 7.6. A 1:2 ratio should equal a pH of 7.3, and a 1:3 ratio should have a pH of 7.15.

In your experiment, a 1:2 ratio should yield a pH of 7.3, but as you try to get closer 7.0 it's harder because RO water doesn't have any buffers that target a 7.0 pH (a pKa for 7.0). The broader the range of pH levels of two different solutions, the more fluctuation you will get; however, when it comes down to getting as close as you can to the target pH, the harder it will be based on other water parameters,etc.

I can google this for you, if you want a clear understanding and reference to what I'm talking about. =)

[Tech Support DD]

To answer your first set of questions, pamdaly:

1. Mixing your well water and the RO water should most likely help to bring your pH down.
2. Yes; it should bring it down safely (many people use this strategy with success).
3. With this new water source system you are using, you may or may not need to add Equilibrium. It will depend on what your resulting GH will be and the GH requirements of your fish and plants. If you are in the correct GH range after the fact, you would not need to use Equilibrium.
4. You may or may not need to use Acid Buffer while using RO water in your weekly water changes. It is difficult to determine what your resulting pH will be. You can certainly add Acid Buffer if you find that using RO water in your weekly water changes is not bringing your pH low enough.
5. We recommend using one or the other; you do not want to over do it with the pH lowering effects of both.

And to answer your second set of questions:

1. It may take some time for the pH to decrease. Your KH obviously decreased faster, but the pH may soon follow.
2. Plant preferences for GH will vary, but a general guide is about 1–2 meq/L (3–6 dH) or to match the existing or target carbonate hardness (KH), which, ideally, is also about 1–2 meq/L (3–6 dKH).
3. The ratio of well water to RO water may need to be tweaked (and will depend upon what you will be able to obtain). Again, whether or not you will need to add Equilibrium will depend upon the resulting GH of the replacement water (and, ultimately, the resulting GH of your tank water).
4. If your KH is 5-6, you would not need to add Alkaline Buffer.

We hope this helps :-)

[pamdaly]

Dear Tech DD,

Thank you for your response. It was very clear and I think I will go ahead and just use the RO in weekly water changes. However, I'd appreciate your thoughts on the following:

1. How urgent is it to get my pH (and KH of 13) down? I have been told that my fish will not thrive in the current levels. I also know it is stressful to change the water too often or in too great amounts and I could end up with ammonia problems. So, if possible, could you give me a ballpark range of time within which I should strive to get the pH down --say, 6 months?

2. It is clear to me from my test mixtures of well and RO water that the pH does not come down near as quickly as the KH. Could you give me an estimate of how long I should wait for the pH to come down before I conclude that I need to add acid buffer. For example, if I'm adding 4 gallons of RO as replacement water to my tank each week for a month and still see no decrease in pH, should I start adding the acid buffer? I may be being too obsessive about this but it's because I'm very concerned not to get some pH bounce that could hurt the fish. Let me know if I should ease up on this worry.

Again, I greatly appreciate your sharing your expertise.

[LabTest57]

Like Tech support DD said, you should tweak your well water to RO water ratio.

Look at it like this: It's harder to change your pH than your kH, so why not use more RO water than well water. Find a ratio that allows the kH to go up to 3 to 6 dkH (preferrably 3), so that the pH can stay on low side (i.e. it will be probably in the 7.2 to 7.6 range). The problem here is that the RO water isn't buffered, so adding well water will significantly change the pH upwards. 1 gallon of RO water + 1/2 gallon of well water (dkH 13) should give you about 6.4 dkH. 1 gallon of RO water + 1/4 gallon well water (dkH 13) should give you about 3.2 dkH.

[pamdaly]

I've just read about "Neutral Regulator" as described on this site under Products. It sounds magical, and too good to be true for my situation...especially since no one has mentioned it. Would this work with my well water and eliminate the need for RO?

[LabTest57]

Well, if your plants can tolerate a lot of phosphate and not wilt and have their leaves turn black, or if excessive algae doesn't starve your plants, then yes you can add it.

Basically, you can do this at your own risk. I've done it before, but it only works if you manually set the pH close to 7.0 to 7.2 and then add Neutral Regulator. After a few weeks, algae should appear and it will take forever to naturally get rid of it.


This product works best for non-planted aquariums...

[pamdaly]

Thanks LabTest57. I have a pretty heavily planted tank so I guess I won't be using it.

[Tech Support AN]

pamdaly,

If you do not see much of a change after a couple of weeks using the RO water, you may want to then try the Acid Buffer method, as this will most definitely bring both your pH and KH down. I do not think that it will take 6 months to achieve your desired pH. To be honest, 7.6 is not a terribly high pH for freshwater and I think that your fish will be able to tolerate it until you can gradually get it to come down. Most fish will adapt to any pH within reason. I have a heavily planted freshwater tank, in which I shifted the pH almost 3 units in one day and my fish did just fine. I am not by any means recommending you to do this, as I was experimenting. I just want to try and ease your mind a bit about fish's sensitivity to pH. I would recommend sticking to your regular water change routine and just be sure to add back beneficial bacteria, such as our Stability, after each change to keep from getting any ammonia or nitrite spikes. To read more about Stability follow the link below:

http://www.seachem.com/Products/product_pages/Stability.html

As for the Neutral Regulator, like LabTest57 suggested, it is better suited for the non-planted aquarium. This is because excess phosphates in a planted aquarium along with all other variables (more lighting, excess nutrients, etc) involved can potentially pose an algae problem, where as carbonate base buffers will not. We hope this helps!

[Cardinals]

Dear Pamdaly
Your water is perfect for African Cichlids!
I am assuming the Total Alkalinity (KH) is coming from your replacement water and not something in your substrate like crushed coral etc?
The challenge for you is that there is too much alkali (base) in your water as indicated by a dKH of 13-15.
If you wish to keep tetras etc at a pH closer to 7, then you must reduce the alkali concentration. There are two options:
1) Dilute the alkali with RO water to say 10%. E.g. 3 gallons well water to 27 gallons RO water. This will give a dKH ~1-2 and therefore a pH closer to 7.0. (you could try this with your spare aquarium first)
2) Neutralise most of the alkali with acid until the same values are reached. “Acid Buffer” will do this, as well as various other acids like sulphuric acid.
The downside with (2) is that although KH/pH may be right, you end up with more salts in your water which is not what “soft water” species prefer.
My preference is to use the RO water option. You could perform 20% water changes weekly with this “10%” water. Consider buying a small RO unit which will work out cheaper in the long run.
Or keep African Cichlids!
Regards
Cardinals

[pamdaly]

Thanks for your response and especially the reassurance that I'm not going to kill any fish with the current pH! I did add about 5 gal RO last evening to my main tank. It did not have much effect on the pH but did bring the KH down a couple degrees (drops). I will continue this process weekly until pH is down and add Equilibirum once the KH gets down to about 6. Let me know if you think this is a good plan.

In appreciation,
Pam

[LabTest57]

I forgot to mention that too as I have a 3000 gallon pond with cichilds with a flow through-like system using well water. The GH must be sky high over 600 ppm, and pH fluctuates from 7.0 to 7.8. I would guess it's from built-up CO2 and a very high kH as well. Im not sure if this is the right parameters for most cichlids, however, my cichlids have spawned countless of times. I have thousands of them. I will shows pics. too, but I gotta take them when they're feeding so you guys can see "the whole family!" :)

[LabTest57]

Here are some old pictures that I still have:

[Tech Support AN]

LabTest57,

Forgot to metnion one thing. Having proper gH levels is required for pH stability as well. Keeping gH at least 1 or 2 degrees higher than kH is a must. Target gH should be in the 4 to 8 degree range for your type of fish.

Having proper gH level is not required for pH stability. gH and KH are two independent entities. General Hardness (gH) is your mineral (magnesium, calcium, potassium) content that DOES NOT impact pH. Carbonate Hardness (KH) is your carbonate/bicarbonate content that is related to alkalinity and DOES impact your pH.

Your GH will be lower because it starts initially lower. If you want your pH lower, use use less well water. Instead of 1 gal for each test, use 1/2 gal. You should notice a difference.

I'm not going by the books in my calculations, I'm just making pure assumptions from intermediate math formulas. If your intial pH is 8.2, you would want to get down one pH level or to 7.2 easy by adding 3 gallons of RO water. A 1:1 ratio should equal to a pH of 7.6. A 1:2 ratio should equal a pH of 7.3, and a 1:3 ratio should have a pH of 7.15.

In your experiment, a 1:2 ratio should yield a pH of 7.3, but as you try to get closer 7.0 it's harder because RO water doesn't have any buffers that target a 7.0 pH (a pKa for 7.0). The broader the range of pH levels of two different solutions, the more fluctuation you will get; however, when it comes down to getting as close as you can to the target pH, the harder it will be based on other water parameters,etc.

I can google this for you, if you want a clear understanding and reference to what I'm talking about. =)

Could you please give me the reference to where you found these calculations. I'm just curious to see how you came up with your numbers....

BTW thanks for the pics. You have quite a family. :-)

[Tech Support AN]

pamdaly,

Thanks for your response and especially the reassurance that I'm not going to kill any fish with the current pH! I did add about 5 gal RO last evening to my main tank. It did not have much effect on the pH but did bring the KH down a couple degrees (drops). I will continue this process weekly until pH is down and add Equilibirum once the KH gets down to about 6. Let me know if you think this is a good plan.

In appreciation,
Pam

Your plan sounds good, however, Equilibrium is going to effect your gH and not your KH. General Hardness (gH) is your mineral (magnesium, calcium, potassium) content that will not impact pH. Carbonate Hardness (KH) is your carbonate/bicarbonate content that is related to alkalinity and will impact your pH. Equilibrium is a mineral replacement ideal for use with RO water. So anytime you do a water change, you can add Equilibrium to the replacement RO water and this will have no effect on your KH or pH. You are simply replacing important minerals that have been stripped from RO water that are needed by your plants for health and growth.


Questions:
1. Why didn't the pH go down as the KH decreased? Does the water have to sit for awhile?
2. You said it was important to keep the GH 1 to 2 degrees "higher" than the KH. It is always lower.


1. KH is measuring the buffering capacity or total bicarbonates and carbonates in the water. The reason you did not see your pH go down consistent with the drop in KH is because the buffers were continuing to adjust the pH upward. As your KH declines to an appropriate level, your pH will begin to decline as well, but you will need to lower the KH by more than you have to see this effect.

2. It is not necessary to keep the gH 1 to 2 degrees higher than KH, as they are independent of one another.

I apologize for any confusion that this long thread may have caused you, but I just wanted to clear up a few things after reading back over all of the posts. Please let us know if any of this does not make sense and we will try to explain further.

[LabTest57]

LabTest57,



Having proper gH level is not required for pH stability. gH and KH are two independent entities. General Hardness (gH) is your mineral (magnesium, calcium, potassium) content that DOES NOT impact pH. Carbonate Hardness (KH) is your carbonate/bicarbonate content that is related to alkalinity and DOES impact your pH.



Could you please give me the reference to where you found these calculations. I'm just curious to see how you came up with your numbers....

BTW thanks for the pics. You have quite a family. :-)


When I said that proper gH levels can stabilize pH, it's only if the water contains mostly calcium carbonate. Most tap waters and well waters have a high pH and kH or gH. Calcium carbonate is alkaline, affects both kH and gH, and is affected (i.e. changes to some other form) when the pH drops. If the water contains mostly calcium carbonate for kH and gH, then it's wise to keep the gH a little above kH, because when lowering kH by acid or dilution your probably affecting other mineral salts (e.g. free bicarbonate and/or carbonate ions). In other words, the gH might actually be lower than you think, and your fish can get stressed if the water softens really quick. Since calcium carbonate is alkaline, it keeps the pH slightly alkaline until a strong acid or a high saturation of CO2 in the water breaks/converts calcium carbonate.


For my calculations of pH, I've gathered info. from other articles saying that it's better to test the pH in these ranges: 6.0 to 6.8, 7.3 to 7.8, and 8.0 to 10.0. If the aquarium water is more alkaline than the water that's going to change it, I would substract the the pH values in reverse order and vice-versa, as well as for an aquarium for acidic pH. Then, I would divide or multiply the result depending on the volume of water being replaced. Sorry, I don't have time for searching this on google right now as I have to paint a house a right now. Later I will search you a reference. :)

[Tech Support AN]

Ok, to be honest with you this post is a bit confusing, especially for the average hobbyist. If the pH drops to a certain level, then calcium carbonate is going to dissolve, which in turn will increase your gH as it releases minerals back into the water. At the same time, you are dissolving a lot of your carbonates with the low pH and decreasing your KH.

If the water contains mostly calcium carbonate for kH and gH, then it's wise to keep the gH a little above kH, because when lowering kH by acid or dilution your probably affecting other mineral salts (e.g. free bicarbonate and/or carbonate ions). In other words, the gH might actually be lower than you think, and your fish can get stressed if the water softens really quick.

When I think of mineral salts I think of magnesium, calcium, potassium, etc. Carbonate salts are carbonate and bicarbonate. Carbonate minerals are calcium carbonate, magnesium carbonate, etc.

[LabTest57]

I've created some calcium carbonate, whether it be scaling or an insoluble solid, and it doesn't dissolve until the water reaches a pH below 6. I will show you next week, a picture-by-picture experiment I can make that proves that calcium carbonate doesn't dissovle so quickly. It takes strong acids or a very low pH water (over time) to dissolve the so called "insoluble" calcium carbonate salts. :)

[LabTest57]

When I think of mineral salts I think of magnesium, calcium, potassium, etc. Carbonate salts are carbonate and bicarbonate. Carbonate minerals are calcium carbonate, magnesium carbonate, etc.

Gh is usually comprised more of calcium ions and calcium carbonate salts.

[Tech Support AN]

According to an Environmental Toxicology textbook (Wright and Welbourn 2002) the principal components of water hardness are the divalent ions calcium and magnesium. The EPA defines hardness in terms of calcium carbonate equivalents: 1 dGH is defined as 10 milligrams (mg) of calcium oxide (CaO) per litre of water, which is equivalent to 0.17832 mmol per litre of elemental calcium and/or magnesium ions.
In water testing, paper strips often measure hardness in parts per million (ppm), where one part per million is defined as one milligram of calcium carbonate (CaCO3) per litre of water. Consequently, 1 dGH = 17.848 ppm.

I do not recall saying that calcium carbonate dissolves quickly, but that it would begin to dissolve at a pH below 6 and at that point impact your GH by putting minerals back into the water. I do not doubt that over time with a pH of less than 6, you will see calcium carbonate dissolve. However, if you want to do the experiment, we will be very interested to see your pictures. :-)

[LabTest57]

Sorry, I'm not going to be able to show pics. I don't care if I'm wrong, however, I would like to point out that the reason being is the following: I could not get more than 10% of any calcium carbonate to dissolve under a pH of 6---in a 35 gallon tank (I was using) with a calcium carbonate solid that is 2 milimeters thick formed (spread-out) on a 2.5 foot by 1 foot surface. I think that because of the amount of calcium carbonate in the water, any acids that were introduced were neutralized when some calcium carbonate dissolved - increasing the kH (the factor in the acid neutralization).

So yes, overtime it can dissolve completely. It takes strong acids to dissolve a lot of it in a short amount of time.
__________________________________________________ ___________________________

Lets get away from this....

New topic (relevant to this thread):


I was doing some calculations on % water changes to time-of-water-change (day/week/month) ratio or whatever.


Okay if my tank starts out with 20 ppm of nitrates and every month it gains 20 ppm nitrates, a 50% water change every month should result in 20 ppm or the intial amount of nitrates (unless the bio-load changes).

If I do a 25% water change every week instead, I would end up with a lot less nitrates by the end of the month through this equation: 20+ (20/~4) x 0.75 = ~ 18 ppm at first week; however, if used as a function you will notice a ~ -0.9 drop in total nitrates compared from the last 25% water change.


So, a higher frequency of water changes with 40%> (less than) water replacement is recommended to avoid pH/gH shock and serves as a better way to lower nitrates and organics, instead of doing large water changes every month(s), right?

I've changed my water change shedules due to this... =)

[LabTest57]

this equation: 20+ (20/~4) x 0.75 = ~ 18


Avoid "Order of Operations", just calculate from left to right no matter what (I put them in wrong order). :)

[Tech Support LK]

So, in a normal aquarium setting, GH and KH operate independently of one another and the test kits that hobbyists use to measure GH detect divalent cations. One should not get confused that these (GH and KH) are, in fact, separate measurements.

Labtest57, please be assured that this is not abut proving anyone wrong, but instead about making sure the hobbyist is not confused in regard to this aspect.

Your calculations are accurate (assuming your nitrates accumulate at a steady daily rate). Performing more frequent, smaller water changes will be more effective at controlling nitrate levels. Smaller water changes will also most definitely be less stressful on the animals.