pH, KH, CO2, etc.

[mordor]

For last week I was trying to adjust pH in two tanks. I am using RO water so I got KH about 20ppm. I was using Seachem Acid Buffer. I was adding half of recommended dose every evening. I got electronic pH meter so I was able to measure pH levels many times during a day. I am a little bit confused and worried about my fish. Here come results. Just after adding acid pH goes down do 3.5. After two hours it's about 4, next day 4.5 and next evening is back to about 5.5-6. In result in one tank I was able to get from 6.5 to 5.5 in one week. Assuming that I got these swings every day I am not too happy about results. In other tank I cannot get below 6.

What am I doing wrong? Too big dose? Shall I increase KH?

 

[Neil]

What fish are you keeping that you need to get your one tank below 6.0?
If you are manipulating you pH with chemicals, you need to do it slowly. So, yes, I would add less acid buffer more regularly. If your water is slipping back up you might need to raise your KH a little. I don't know whether Seachem does that or not.
I would mix a solution in a seperate container and then do daily small water changes to get the desired results.
I have used pH Down a number of times to lower the pH for a difficlt species, but I usually do it when I think the fish are close to spawning, so I don't have to keep it down forever.
Again, I am not sure what you are trying to achieve. But if you are trying for a longterm low pH, you will probably need more than 20ppm KH. I don't believe that is enough buffering without having to"slowly" and regularly add more chemical.
Neil

 

[mordor]

I think I learned the lesson. I will be even more caucious next time.
First and this is more serious for couple days I was measuring just one time a day so I kept adding acid buffer because I got result that pH was 6.2. I didn't know that just after adding chemicals it was 3.5 and returned to about 6.2 during next day when I was usually making measurements. It seemed to lower pH 0.03 a day but actually I did have huge swings.
Second if I am mixing acid buffer with water I have always check pH of this solution. If water is so soft there will be no buffering and even I am using less than manufacturer recomended dose and if I am introducing liquid that has pH 2 into water it will have huge effect on it. I bought alkaline buffer and I will be mixing with acid buffer until I get pH about 1 less than in my tank. This way there will be no chance to go below pH of the solution and also KH will increase.
Third, Aggasizi spawned when pH was about 4.5 It's now 5 and not going to alter it more. It will come back to 6 in 1-2 days I guess.