m0useanswered grow question 3 years ago This may not be a cause but when using BioBizz, let your nutrient solution sit out for a night or 12hr before adjusting ph.
Cover it with a towel or something, The feed tends to drift down in PH as its allowed time to mature in the water.
I'd also get a TDS pen so you can to confirm its EC is on point for where you want it.
Good Luck!