RO Water Treatment

[Chester]

Greetings,

I was wondering if there was a guide or someone could explain how to correctly treat RO for stable use in a freshwater aquarium.

Im on a well, so tap water is not doable for me. It must be 100% RO.

What must I do or add, and in what order to obtain a rock stable ph of say 7.5?

Believe me, many, many thanks in advance to whomever answers this.

Cheers
Chester :)

[Tech Support JS]

Chester,

Thanks for posting. The avenues to answer this question depend on which type of tank you have, so I will try to give an all-encompassing answer.

The first think you are going to want to do is replace the beneficial minerals that you removed by the RO process. If you have a planted tank, you can use Equilibrium to accomplish this. If you have a non-planted tank, you can use Replenish. Both will accomplish the same goal, but are specifically designed for either the certain type of tank.

Secondly, your pH is an issue. You said you wanted a pH of 7.5, so if you have a non-planted tank, I would suggest using a combination of Neutral Regulator and Alkaline Regulator to achieve your desired pH. These are phosphate based buffer and are very stable and reliable in freshwater, non-planted aquariums. If you have a planted tank, I would suggest using Acid Buffer and Alkaline Buffer at a specific ratio to achieve your pH. These are carbonate based buffer and are very reliable for freshwater planted or saltwater aquariums. The ratios for all the products can be found on the label or on the website.

After accomplishing these two goals, your aquarium should be set to go! Thank you for your post and have a great day!

[Chester]

JS,

Thanks for the reply. I’m going to tell you about my setup and echo back some of the advice you have already given me to make sure I have this stuff figured out.

First off I’ve been trucking in water from town for a very long time and its getting tiring to do so. Me being an old guy and all.

I do this as my well water has a very large iron content and the anaerobes that generate Hydrogen Sulphide gas. So I decided to try an RO system. The water itself now passes through sediment and a green sand filter, then to 2 carbon blocks and finally a 0.3 micron filter before ever hitting the RO unit. The RO output is then passed through a deionising chamber. I just got a TDS meter for it but don’t yet have it installed. So I’m hoping this generates some nice clean water.

I was reading all over the net that folks had given up on trying to use 100% RO water due to wild ph swings. Even with buffers. They resorted to mixing tap water and RO to gain some stability. Reading all these accounts was cause for concern me. I need a fairly stable ph.

So lets look at my process so far, and we will assume that plants will be used in a few of my aquariums.
Water will be prepped in lots of 100 gallons.

1) let the water stand for 24 with air bubblers going to remove any Hydrogen Sulphide gas and establish normal O2 levels.

2) Add “Equilibrium” to get my essential minerals and GH where I wish it to be.

3) Add “Alkaline Buffer” to achieve my desired PH (7.2 - 7.5) I assume this is KH?


This is what I understood from your note. This simple system will result in a rock stable PH?

Did I miss something??


Cheers and Thanks again!

Chester

[Tech Support JS]

Chester,

It sounds like you have a pretty good setup, and your RO assembly should be very effective! Thats an interesting thing going on with your hydrogen sulfide problem, and since hydrogen sulfide (H2S) almost chemically mimics water (H2O) [unless you want to get into really technical chemistry, which I love!], so your RO unit will have a tough time separating it. I agree with your aeration method, but it must smell with all of that H2S in there!

Equilibrium is definitely what you would want to use to get your GH up if you have plants.

Since we are going plant based, you are correct in the Alkaline Buffer, but I would strongly suggest using it in combination with Acid Buffer to achieve a more stable pH. This may sound odd, but I will explain: Alkaline Buffer has a very high 'pKa.' The pKa of a chemical is where it will want to pull the pH up to, so using Alkaline Buffer alone may increase your pH more than you would like, especially in RO water. Acid Buffer will work to 'fine tune' your pH and not allow it to creep up exceedingly high. The ratios are listed on the bottle, and are Dose-Dose, not a direct ratio, so for clarification I will list an example:

If are starting a new tank of 60 gallons using RO water and want a pH of 7.5:

1) Find the ratio: Here, the ratio listed on the bottle/website is 1 dose of Acid Buffer to 2.5 doses of Alkaline Buffer.

2) Find the dosages for each: Per the label instructions, one dose of Acid Buffer is 2g (1/4 tsp) per 20 gallons; one dose of Alkaline Buffer is 7g (1 tsp) per 10 gallons.

3) Calculate the dosages for your tank: For 60 gallons, one dose of Acid Buffer will equal 6g (3/4 tsp) and one dose of Alkaline Buffer will equal 42g (6 tsp).

4) Multiply the dosages by the ratio: Here it is 1 Acid::2.5 Alkaline, so..

You would want to add 6g (3/4 tsp) of Acid Buffer and 105 grams of Alkaline Buffer. Here you can see that you will obviously need more Alkaline than Acid Buffer, and that is because the Alkaline Buffer is where you will be getting your KH, or carbonate buffering capacity, and the Acid Buffer counters that by converting a small amount of your carbonate into CO2 to ensure that you do not unintentionally raise your pH.

You should continue this calculation for water changes, but only to the replacement water (if you replace 10 gallons, only do the calculations for 10 gallons and ad it before you add it to your main tank).

I hope this information helps and I am glad to help!

[Chester]

JS,


In so far as the hydrogen gas, I did omit to tell you something. The first time I ran the RO unit, the product water smelled like rotten eggs! To me, that was a definite - what the hell! - moment. The I discovered that the gas passed right through the RO membrane! The water before treatment in the RO unit didn’t smell that way, so something was masking it.

So, heres what I did about since I was not happy at all having the dangerous gas in my water not only for the fish, but for me and my wife too! First thing I did was nuke the well with bleach. Once the bleach was in, I ran the garden hose back down the well till I could smell bleach in the discharge of the hose. Then I ran all the taps in the house till I could smell bleach also. I let that mixture sit in the well and system over night. Over the next few days, I flushed the system many times. Till the bleach was gone.

The next step was to get air to the very bottom of the well. I got an old diaphram type painters compressor and ran an air line with several air stones to the bottom of the 100 ft well. I began to increase the air pressure in the line till I got bubbles at the surface. It took 44.7 PSI to over come the pressure of the water at 100 ft deep. The intent here was to rid the water of hydrogen before it ever gets to the house. This was a success. However it made the water quite turbid and took a long time to settle down, after 30 years of iron sediment, well Im sure you get the picture. This system runs 24-7.

I still run air through my product water just in case. I don’t smell rotten eggs anymore, but its better to be safe than sorry.

If you like water chem stories here one that just happened to me that will blow your socks off. This is what inspired my to get my butt in gear and get my own treatment system up and going.

As I told you I have been trucking in all my water from the local town. For a very long time. Recently I had a chance to buy a small in tank UV systems cheap. So, I started a brand new 20 gallon tank with this town water, brought it up to temperature, treated it with the usual stuff to deal with chlorine. Turned on the UV system and let the water circulate. 6 hours later, I stole some of the water out of the tank to fill a 5 gallon tank as I brought home 2 new pictus cat fish. See I quarantine all new fish for 30 days in small 5 or 10 gallon tanks. After this, I topped the 20 gallon tank back up with treated town water. The pictus cat fish looked happy in there new home.

12 hours later, the cat fish where very very sick. There spines where bent like hockey sticks!! I thought right away it was neon tetra disease!

Then I went to check that new 20 I just started. When I opened the top, it stunk like burnt chemicals real bad!!! I thought the UV lamp was burning the plastic case!! So I took it apart. It wasn’t it was fine!

After an extensive search, I found out that the UV lamp was catalyzing something in the water! What I dunno but it was BAD!

I lost everything plastic in the tank. The gravel, the filters… everything. The water left a white residue at the water line that was hard to get off. It was kind of greasy.

The water killed the cat fish in short order. They both looked like the letter L when they died. Pretty much bent a full 90 degrees.

I have no idea WHAT chemical reaction was happening. Can you shed any light on what might have been happening? I have the towns spectrometer report, I can fax it to you if your interested. I would be good to make this problem public so others can avoid it.

Im off to the LFS tomorrow to get the product you have mentioned. The water coming from my filter system is crystal clear and great, but I think im gonna go RO after all this chemical nonsense. Right now Im mixing 25 % filtered water with 75% RO water and getting good results. But god only knows whats in that 25%. Looks, smells, tastes good, but based on the above, that clearly means nothing.

This experience has really opened my eyes to the problem of pollutants in our local water shed. Town water I WAS using is a small northern Canadian town surrounded by pristine lakes and forests. I never would have guessed it.

I appreciate you help, and will report back my findings when I begin to mix 100% RO water.

Cheers

Chester.

[Tech Support JS]

Chester,

That sure is interesting... I think the chlorine shock should definitely kill the sulfate-reducing bacteria that are causing the smell, and since they are anaerobes pumping the air should do the trick, even though you have to pump it at a pretty high PSI! As for your 20 gal tank, that is odd to hear. I dont know what the UV could have done, especially since you didn't dose anything (I assume), but even if you did, I have never heard of that happening. Out of curiosity if I were you, I would fill the tank back up with the same water but no fish and see if the same thing happens again. Anyway, I go with 100% RO and have had no problems, so that is always a safe option. Thanks for posting about this case and I wish you the best of luck!