Would like to get suggestions on the amount, type, depth of substrate that would be good for this tank. Little apprehensive with using flourite, onyx sand, because of nutrients leaching into the w/c, and giving me problems with the fish. Seem to be running a fine edge here-I don't want to screw up the w/c, but the plants need nutrients to flourish. Thought about using pots-anyone have a good substrate formula for an aquarium pot? . All thoughts and comments would be appreciated!!