When I feed until I get 15% runoff or so, how long are we waiting to determine that the runoff is "over". Are we talking minutes, hours or how long. I will have alot more runoff after an hour or so than just shortly after feeding. Also, to check ph of runoff, should I catch the very first runoff that comes out, and as long as I have sample enough to stic the tester in, is that enough? I've run 3 grows paying no attention to ph what-so-ever, so this area is all new to me. I really didn't notice any problems with my previous grows, but I may have been missing out and not even knowing it. Thanks for any help.