KH = 1; GH = 2. What do I do?

Steven, what are the fish species in this tank (present or intended)? And what plant species? This should govern any fiddling with the GH and KH. Also, do you intend using diffused CO2, or staying natural? I will offer what I can when I know this data.

Byron.

Steven 1 said:

Byron,

I have a 10g tank with six Pristella Tetras. pH used to be 7.6 (with gravel substrate, before dirt), KH 3, GH 5.

The fish are eating well, high-end flake food. I don't think the fish are the problem for the moment - it's the plants. I have some Cyanobacteria. There's some dissolved organic carbon that I have to siphon out pronto. And I do have pretty strong lights suspended over the tank six inches. I should take down the photoperiod from 9 hours to 8 hours.

I also need to resume 50% wc per week - I've lapsed for a few weeks.

I have 3 ruffled? Swords, a couple of crypts, some plants that I ID'd as Water Weed, Java Moss, and some plants that grow in a circle and have some pink on top. I'll post a pic tonight.

I'm going to stay low-tech (no diffused CO2) and I don't know, maybe I'll add a school of dwarf corys.

Thanks very much Byron.

Steven

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This tells me a lot, thanks. I expect you will remember from our past discussions elsewhere that I have never messed with dirt substrates so my suggestions are more general in nature rather than from direct experience.

First, soil substrates tend to cause various problems during the first few months, with many reliable sources suggesting six months. During this period, ammonia is likely to rise, so keep an eye on that; the plants will not be able to fully handle this, so it can be severe. This unsettled situation and especially with the high organics in the soil is the cause of the cyanobacteria. Water changes should be substantial during this entire period.

Lighting with soil should not be bright. Moderate light is what the soil enthusiasts suggest. Remember that reducing the duration can help, but the intensity itself is still significance whatever the photoperiod. The plants mentioned are low and moderate light requiring, except perhaps for the un-named which your photo may help with.

To the parameters. If the GH was 5, presumably this was the source water (tap)? Unless something calcareous in the former gravel raised it. That is ideal for plants, just right on. I expect the organics in the soil that are decomposing will lessen the GH. Adding it back via Equilibrium is one option. Removing the soil and saving money on Equilibrium is another of course.

I wouldn't worry about the KH. Mine is zero and has been for over 20 years. As long as you stay with soft water fish you are fine if the pH lowers. But it obviously can go too far, and here regular weekly water changes will prevent this. What is the pH now?

Byron.

OK, with the new numbers for GH, presumably this being the tap water, you will need to add the "hard" minerals and Equilibrium is about the easiest way to do this. Bring the GH up to 4 or 5 dGH and the plants should be fine. Named fish won't have a problem with this either.

The KH I would still not bother with, but be regular (weekly) with 40-50% water changes, and check the pH from time to time, prior to the water change.

Byron.

Steven 1 said:

Thanks! I always had about 3 dKH and 5dGH with 50% water changes per week with about 3 dGH Equilibrium. There is a lot of peat in the MGOCPM. I saw the pH go from 7.6 to 6.7 and back up to 7.6

So I can expect to maintain the buffer with the 50% per week water changes and GH with water changes and Equilibrium.

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I would expect the pH to lower below 7 and remain there, after perhaps a few weeks. My 50% water changes with tap at 7.0 to 7.2 and tanks running at pH 5 (some) or 6.4 do not affect these levels. The tank's biological equilibrium over-rides. The cause of the tap water pH of course plays into this, and yours may be different.

Byron.