My tanks pH is 7.8-8.0 and I'm not sure why.. I do tops offs and water changes with pure RO water.. I don't remember if I started the tank with pure RO water but I think I did. It's only a 30 gallon well planted and nearly fully stocked.. The tank has been up for over a year now. Everything is doing fine except for some plants mainly my mosses and the only thing I can think of is the pH.. What is raising the pH? I only have driftwood, petrified wood, and the fluorite enriched gravel in there. I do have one sizable rock in there but it's not a lava rock and shouldn't effect pH.. Any help/suggestions? Thanks!