What Else Other Than CO2?
I am wondering if anyone could guide me in the right direction. For the past 4 months, I have been adding, to my 75 gallon planted tank, only CO2. For substrate, I am using, what was described to me as very fine crushed granite. I purchased the gravel along with the plants. My question is, should I be adding anything else to my water aside from the CO2? I was wondering if I should add anything to my substrate being that it is artificial? Also, how often should I be making water changes? I read in a site, that I should make 25% changes every other week? I don't want to take so much CO2 from the water. Any help would be greatly appreciated.