PH down..how much do I use?

[Bongojaz]

I suggest you guys first mix your nutes and then check the pH. Most nutrients will stabilize the pH. It does not make much sense checking the pH of almost pure water and then stabilizing it. After you add all your nutrients stabilizing is not a problem.i

^^^what he said!^^^
you want as little ph up/down, in your mix as possible. i don't even use ph up. i use pro-tekt for that.