How to raise KH and GH safely? - The Planted Tank Forum
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post #1 of 6 (permalink) Old 03-31-2011, 06:51 AM Thread Starter
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How to raise KH and GH safely?

I have 8 juvenile discus in my 60 gallon tank. My water out of tap is 6.7 - 6.8. My GH is 0-1 and KH is 1. I recently added a little alkaline buffer in the last water change raising my KH to 4 and PH to 7.3. I want to inject c02 so need to get my GH, KH and PH levels up. Does anyone have experience with Seachem Alkaline buffer? Whats a good product to raise my GH? I am assuming that adding and raising my levels slowly over the period of a few days will be safe for my fish. I do not want to cause any unnecessary stress. Is there a technique that I should follow to do this?
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post #2 of 6 (permalink) Old 03-31-2011, 06:57 AM
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I'm not really following your logic. You're planning on adding CO2, which is fine. Why do you feel like you need to increase your KH, GH, and pH to do that? Adding CO2, regardless of what any of those parameters are, won't harm your fish. Your buffer can potentially do more damage to them than CO2 will.
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post #3 of 6 (permalink) Old 03-31-2011, 07:28 AM Thread Starter
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My water out of the tap has almost 0 buffering capacity. When I inject c02 my ph hits the low 5 range and with 4 watts per gallon lighting I need to have even more c02 thus bringing my ph even lower maybe even into the 4 range. At such a low c02 ph range wont it eventually become harmful to either my fish or plants? Or have a harder time dissolving into the water? Since I am trying to avoid hitting such extreme low ph values with my c02 I basically have been growing black beard algae. I want to be able to inject more and be within a normal 6.5 ph range for a discus tank. Plus I was hoping to stay in the 6 range for the health of my discus. This is where I might be contradicting myself, isn't my water ph already within the discus 6.5 range and adding c02 is just altering the ph number not the TDS etc?

I was going to increase my GH for the sake of my plants getting the calcium and magnesium they need from the water.

Maybe I should just reduce the lighting all together, needing less c02 and less nutrients and making my life easier. The reason I upped my lighting so much was because my tank is pretty deep at 32 inches and growing carpet foreground plants was difficult. Seems like the more watts the more trouble I've gotten myself into. Even at 2 watts per gallon won't it still be beneficial to have at least some type of KH value in my water rather than 0-1?
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post #4 of 6 (permalink) Old 03-31-2011, 09:35 AM
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If you decide you do want to increase these levels you should check out this - very cheap and easy, though obviously for your purposes you would use much less:
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post #5 of 6 (permalink) Old 04-01-2011, 06:15 AM
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CO2 can't lower the pH much below 5.5, if that low. At normal aquarium water temperatures, that is about the bottom limit for pH due to CO2. (I think this is because no more carbonic acid is formed once the pH is that low.)

If your KH is above 1 degree of KH you have as much buffering as you can get from KH. Increasing the KH further just raises the pH.

It is safe to raise the KH with baking soda, but not necessary to raise it above the 1-2 range. And, once you start adding baking soda to adjust the KH, and GH booster to adjust the GH, you are stuck with having to match those adjusted values with each water addition to the tank. Of course small variations aren't a problem, but adding half a tank of 1 dKH water to a tank of 6 dKH water is not a small variation to the fish. It is an abrupt drop in half of the KH. This still might not prove to be a problem, but how will you know for sure?

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post #6 of 6 (permalink) Old 04-01-2011, 06:45 PM
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I have used Seachem Equilibrium to raise the GH in planted tanks, with soft water fish and hard water fish. The key is to know how much to add. There is a recipe on the jar. Try half that, and see what it does for your tank. I dissolve it in a jar of water (it takes a lot of shaking) then add it to the tank, or else add it dry to the water I am preparing for the next water change. A small pump to move that water around will usually dissolve the Equilibrium. Barr's GH Booster is just about the same ingredients, but seems to dissolve easier.

Baking soda for KH is OK, but I would just maintain 1-2 degrees, no need to go higher.
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