JCTJ
Well-Known Member
It's not the pH of your water that matters, it's the alkalinity. High alk water will raise any the pH of any medium over time, but I would think the ProMix would handle a single grow without modification.
And just to reiterate, lowering the pH of your nute water will not change the pH of the medium or affect the rate of rise over time. If you're worried, you could consider adding lime to the mix before using it. I'd ask @farside05 for details on that modification.
I finally looked up my local water alkalinity and I'm at 290ppm avg, 250ppm min, 340ppm max. Should I be looking into things to add/change for future grows?