pH high... don't know why?
I'm puzzled as to why my pH is so high in my tank (7.4 - 7.5). I have a 12g heavily planted nano cube with DIY CO2, eco-system complete substrate, 1 piece of driftwood, and I use distilled water for water changes. I also dose excel and flourish. My ammonia, nitrate, and nitrites are very good; it's just my pH that seems high, especially since the water I use has a pH of about 6.4. What would cause my pH to be so high? I thought if anything my pH would be low if I am adding CO2 and my water I use for water changes is low to start with.