is it normal for the water runoff ph to drop to slightly more acidic? starts at about 6.3, then the runoff drops to about 5.8. im guessing this is normal and i hope so. whens a good time for a little flushy? thanks in advance.
No it's not normal for runoff to be 5.8...that indicates your root zone is 5.8 and this is incorrect for soil (perfect for hydro).
so im assuming then that the prewatering ph should be a little over 7 to get to a more 6.4ish runoff? is there a point where you can use too much PH up?
Sadly, that's why I personally avoid using soil. See, you can take 7.0 pH water and dump it into a plant's soil only to get runoff that is 6.3.... or visa versa. It's all about the pH of the root zone itself, which I have never enjoyed having to 'correct' once the lady is growing in there. No sir...I'll stick with easy ole' dro... Hopefully another soil-chief can help ya out with this debacle.