I think promix recommends 5.5-6.2 for ph. Id try around 5.8-6.0. Mine stsrted hsving problems at ph 6.5. So i eould think a bit lower than 6.2 would be best. All i can offer is an opinion. Trust your gut.other than starting nutrients early on low dose and ph for soilless, use cal mag starting sround week 3 especially with the qbs i dont see where youll not be happy. Im actuslly about to go get another 2 or 3 bags of promix. Worried they might not stock it over winter. I doubt they do and i might be screwed til march or april.
i uzed straight ffof for my current second grow (if u could still call it that, lol), but only becuz it was all the rage about 5 yrz ago when i did me first grow...but i admit to not keepin up with thingz in the meantime, and thus, didn't learn of all the quality control issuez that have cropped up with all ff soilz, and guess i have inadvertently paid the eejit'z price as a rezult
my ffof has been 7.5 ph from the start in my current grow, and has been a nightmare to deal with, tryin to figger out all the sudden-outa-nowhere nute imbalancez that started happenin right after preflower hit...ahh!!
it'z def too hot, or at least mine has been, lol
so anyway, no, me not a fan of ff soilz now, but unfortunately, also happen to have a brand new bag of the frog sittin here that i was gonna go with for me next grow, but now, i'm seriously re-evaluating, lol
i've also got a new bag of perlite, so there'z that at least, but at the least, i wanna cut it with sumthin else as well, to weaken it a bit, but jus haven't decided what yet & still got a couple weekz to decide, so...jus me own 2 ct story
ppp