Try grabbing a solid PH down from TechnaFlora or other manufacturer. If you're using natural up/down base & acid's they don't contain the buffers to help fight back the PH rising. You will need to use real PH down diligently until you get to a point of balance where it takes less and less intervention. The natural PH adjusters you're using contain nothing to help retain and buffer that PH from rising (as fast), but rather to just add an acid or base to adjust it to the number you want.. that could be one reason you're finding you "must" adjust PH by a point or more every 12 hours.So my leaves are curled.. I beleave the hydroton 8mm-16mm crushed my roots and the must be in shock. maybe the nutes to strong for this seniero gonna step down to 1ml/1gal. ph goes up one point in 12 hrs, treated 3 times w/ molassas and vinger. all when I changed Resivors from 3.5 gal to 5.gal. Thoughts are welcome.