(Well You might remember a while back that I had trouble (on a different forum) with my Ph being 6. It's a livebearer tank, so of course I was concerned.
I bought some "correct Ph" from wally world, and it totally messed up everything. (my water turned milky white overnight, all fish were at the surface, and 6 died. Also, the PH didn't even change.)
So, I did what I could to save the fish. Did lots of water changes, and increased aeration since the fish were at the top, which to me is a sign they were having trouble breathing.
I got a few suggestions, like calcerous gravels and crushed coral. Unfortunately these were too expensive, so I put some thought into it. Corals and calcerous gravels revolve around calcium carbonate. I knew I'd learned something else that was calcium carbonate... and then I remembered.
After the fish seemed better, I added a stick of chalk. (all in the course of a day- I know, risky, don't get on to me, it's a learning process. Plus I know a PH of 6 bad for gups.
I added the chalk, and the next morning tested PH. It was 7.5. W00t! After much celebrating, I went on with other things. Today, I tested the PH, and it was 6 again. I added more chalk, but wait- No water changes after the last chalk piece, how did it go down? I know nitrates can lower PH so thats what I THOUGHT the problem was.
Turns out I had high co2 levels (explains why I had 10 flower spikes at a time from the aponogeton, and why I lost 5 guppies and my beloved ghost shrimp over the course of 2 weeks)! Levels over 25 are toxic to fish- my best guess now, was my level was somewhere between 40 and 75. I switched out my weakling air pump with a more powerful one, and in 30 minutes my ph went from 6.0 to 6.2. I'm hoping that the oxygen supplementation doesn't prove too shocking for the fish, but in an effort to correct this problem, pretty much my only option is a trial by fire, and see where it goes :-/. IT's a bad idea, sure, but short of standing by the plug and plugging in/unplugging the pump every 20 minutes, I don't think I have any options.
Anyway, still going...
I think I figured out why my water turned white overnight- This is my reasoning.
The PH stable tablets contained a chemical that behaves similiarly to CaCo3, Calcium Carbonate. 24 hours a day, the fish produce CO2. At night, the plants stop absorbing it. I know from Wikipedia these two facts-
Calcium carbonate is poorly soluble in pure water (47 mg/L at normal |
atmospheric CO2 partial pressure as shown below).
The equilibrium of its solution is given by the equation (with dissolved
calcium carbonate on the right):
CaCO3 Ca2+ + CO32–
Ksp = 3.7×10−9 to 8.7×10−9 at 25
where the solubility product for [Ca2+][CO32–] is given as anywhere
from Ksp = 3.7×10−9 to Ksp = 8.7×10−9 at 25 °C, depending upon
the data source. What the equation means is that the product of
molar concentration of calcium ions (moles of dissolved Ca2+ per liter
of solution) with the molar concentration of dissolved CO32– cannot
exceed the value of Ksp.
Which , I think, basically means that at a certain point of both of them increasing, something has got to give. I don't know the term, but basically, the CaCo3 and Co2 in the water were competing for the same space in between the water molecules. At some point, one of the guppies inhaled, and exhaled that one extra bit of Co@ that broke the camels back. (It's funny to imagine, inhale, exhale, then suddenly POOF all this white stuff appears. Doubt it was that sudden though)
The CaCo3 (or similiar compound) was forced out of the H20, and into the "water". (ie, it wasn't really dissolved anymore, rather tiny tiny particles were drifting in the water which made the water look cloudy. Also, it's why, when I increased aeration and did a 50% water change, the residue that was left finally dissappeared (dissolved back into the water). Right now, I'm out of test strips so I can only test PH. However, CaC03 dissolves in acidic water, and is relatively stable in base water...
So I'm going to leave the chalk in, and test the PH to make sure it doesn't get too high, so the chalk will be a sort of "insurance policy" if there's a power outage or something. It's just setting on the substrate, so I can take it out easily. (worst case scenario, I don't monitor it, and the chalk dissolves into it's max concentration for dissolved water, placing the PH at 8.7. However, since CaCo3 only dissolves at a rate similiar to it's decomposition rate, I highly highly doubt the PH would go above 7.4-7.8, as long as it's away from direct water flow and I don't force it to dissolve.
Argh, I forgot my questions... Oh, that's rihgt. If someone was using CO2 supplementation in a heavily planted tank (knowing exactly how much CO2, and keeping the CO2 levels the roughly the same, and at a relatively low setting) does anyone know if CaCo3 would keep the PH from fluctuating, at all? Basically, my goal right now, is to get my PH to 7.4, and Kh at 10-12, giving me a CO2 level of approx 12-15 ppm.
If you don't know, can you at least agree that 7.4 ph and Kh of 10-12 are good for gups?
If it seems overly complicated, it's not. It's the same as using calcerous gravel or crushed coral, just in a much cheaper (and purer) form. (chalk is 99 cents for enough to last me a long time if I resist drawing with it. :))
Wikipedia-CALCIUM CARBONATE Calcium carbonate - Wikipedia, the free encyclopedia
Measuring CO@ levels in a planted tank- Copyright 2000, Chuck Gadd- Measuring CO2 levels in a Planted Tank
(maybe this will help someone. I know it would have helped me two weeks ago)