hey IF: have you actually run PPKs w/pH down around 4.9?? what happened?
*To be clear, I should specify nutes in the bulk reservoir (and this predated Jacks in my grow, so those recipes were pretty scary).*
The plants grew.
I ran them in temps over 108 too.
The plants grew.
Ran them with just RO top off for a week.
No one noticed.
Spiked EC to 4ish something.
Plants grew.
I think its all in the beginning of the 'Interpretation'/'Overview' thread I wrote and is in my links... once you get past the first few pages of 'interpretation'/'Overview' bullshit.
(Um, they grew better in more moderate climates, with less ridiculous feed recipes... but they kept growing in all that absurdity. It was not a preferred location at the time with preferred controls, but it was all I had.)