Due to the acidic medium, I decided to water with 6.5 PHed water (no nutes) instead of a normal nute feed for one cycle. The next feed the nute water was 6.8PH and the run off was 6.5PH, much better than 7-6 I'd had in the past few feeds. Also started to show signs of too excess nutes, so I've reduced the grow by 1mL/L