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KH too high?

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  • KH too high?


    I recently set up a new planted tank and am wondering... is my KH too high? It's 10 degrees. While I guess that isn't horrible, it is out of the range of the plants of have, which is typically 3-8.

    It's only been about 2-3 weeks, so I don't much of a baseline to go off of, but growing seems to be going well. I noticed a problem with 2 out of my 3 red cryptocoryne plants "melting" away, but after looking closely at why the 1 seemed fine compared to these 2 I noticed that the roots of the 1 good crypt were slightly exposed. So I slightly pulled up the other 2 crypts to do the same and they seem to fairing better.

    Micro sword, abubias nana, water sprite, cabomba all are growing well. In the case of cabomba and water sprite, both have grew to the top of the aquarium and I have already trimmed the cabomba down a couple times. I had a batch of anarcharis, but those all "melted" down within a week and I just mailed it in on those and removed them all. 2 out of my 3 java ferns had a good bit of black spot algae on them but I have sinceI trimmed the offending leaves off. It should be noted that the 2 infected ferns came to me with the algae already on them.

    Tank is a 75g with a fluval fx5 with biomax in all 3 media baskets. I started the tank up with tap water with a conditioner/dechlorinator added and then followed the "new tank startup" instructions on the bottle of the Cycle product (forget the name brand) to hopefully jump start the biological filtration a bit, but I understand it most likely doesn't do as much as advertised (i.e. immediately cycles). 3" of ecocomplete substrate and a pressurized co2 system at a ph controller controlled 7.0 ph (according the the co2 charts a 10 kh with a 7.0ph is approx 30ppm, which is why i keep the ph there). Also running a uv sterlizier (coralife turbotwist 9w) 24/7 off a maxijet 600 powerhead, changing 15 gallons of water twice a week, 108w t5h0 (1x10000k and 1x6700k) for 9 hours and ammonia, nitrates and nitrates at, or as close as my eyes can tell on the color chart, to 0.

    I'm not doing any ferts as of now and since startup but that is changing today as I have an order of a few bottles of flourish coming in.

    Fish load is fairly small... 2 angels (had them previously in a 29g for the last couple years), 8 rummynose and 4 corys. All fish are doing great. Will probably pick up another half dozen rummy's some day, but not for a little while. That'll be it, though. Again, my KH is out of the typical range listed for rummy's and angels, though.

    Anyways, should I worry about lowering my KH? I know I there are ways to lower my KH, such as mixing in RO water with my tap, but I'd like to avoid that if possible as it'll be a hastle... but would consider it since I want good conditions in my tank, both for the plants and fish.

    Anything else to recommend I check for/do?

  • #2
    Re: KH too high?

    Thanks for the post! Congratulations on your new tank. It sounds as if you have a very nice set up!

    The melting you are experiencing with some of your plants, especially the cryptocorynes, is normal. I maintain a 265 gallon planted tank here at Seachem and we just planted a lot of new crypts and are going through the same thing. Their leaves and some stems will initially melt while they adjust to the new environment, however, their roots will remain in tact and will put out new growth pretty quickly. So I would not necessarily pull those plants out, as I think their roots are most likely OK. If the plants seem to be flourishing, I would not worry too much about the KH at 10. However, if it becomes a problem and you feel like you need to cut it down, you can use our Acid Buffer, which will convert your KH into CO2 and will also lower your pH. Each dose lowers alkalinity by about 0.2 meq/L (0.6 dKH). Keep in mind that this is a very strong acid and will drop your pH rapidly if you are not careful. My recommendation would be to leave your KH alone, as long as everything seems to be doing fine.

    As for supplements, we have an entire planted line of products that will help you to have a very successful tank! I would first recommend the Plant Pack: Fundamentals, which contains our Flourish, Flourish Excel and Flourish Iron. These are the baseline products that you will want to start out using. Flourish is a comprehensive supplement that contains a rich assortment of important micro elements, trace elements and other nutrients that are needed by the plants. Flourish Excel is a source of bioavailable organic carbon that is easily taken up by the plants for explosive growth. Since you have CO2 injection, you may not need this. However, adding this in addition to the CO2 injection will allow for enhanced growth rates. Flourish Iron is a highly concentrated (10,000 mg/L) ferrous iron (Fe+2) gluconate supplement that is also very easily taken up by the plants. Follow the link below to read more about the Plant Pack: Fundamentals:

    In addition to the products above, I would also recommend using a Potassium supplement such as our Flourish Potassium. Potassium plays numerous important roles in the planted aquarium such as enzyme activation, stomatal activity, helps in photosynthesis, and many others. Lastly, I would recommend using the Flourish Trace as well. Trace elements are extremely important and will get depleted quickly through utilization, precipitation, and oxidation, so it is important to replenish them on a regular basis. Below are the links to the Flourish Potassium and Flourish Trace information pages:

    I hope you find this information helpful and please let us know if you have any additional questions. Have a wonderful day!