I should ask this on a FW forum but what the heck let's put some activity in this one ..
I have a planted FW tank, must be coming up on 5 years old, and there's something I've never really been able to understand with this stuff.
I inject CO2 to try to have better plants than algae. For the most part it does not work out. For one, I can't seem to lower the pH of the tank .. at all .. with CO2. In fact, the pH is much higher in the tank than the tapwater is coming out of the tap.
Tap water is around 7.5, the tank runs around 8.5. This is with about 2 bubbles per second CO2 into a cyclone style CO2 reactor inside the tank.
Could the substrate be the cause? I have a mixture of black flourite and a laterite based substrate. Looked like crushed lava rocks though, if that helps.
A couple pieces of mopani driftwood are also in the tank.. could that be helping push the pH up?
I have a couple TLF phosban reactors kicking around somewhere, would it be a good idea to add peat pellets to help bring the pH down? If I do that, how do I know how much CO2 to add to the tank if I aim for a pH target based on the carbonate hardness of the water? (Or would peat bring the KH value down?)
I'll be doing some reading tonight in an effort to wrap my brain around these questions but I'd totally welcome any insights from planted tank gurus .. please and thank you!