Planted FW tanks, substrate, pH and CO2 questions ..

[Delphinus]

Yeah that is the weirdest thing, the water does not stain with tannins, but there is no carbon. When I presoaked the wood for a couple days it made that standing water super brown, maybe it leeched enough that it doesn't stain anymore, but that just seems odd to me nevertheless.

I have probably about 3 gallons of plastic bioballs in the sump and over top of that is some filter floss. Other than than the Tunze that is really it to this tank. I do use a cable heater in the substrate but I don't imagine that has anything to do with the lack of tannins in the water.