Long time fan, first time growing

The BB is in Flower and looking good, she's been stretching ( 46cm day 37) and the flowers are noticeable getting hairier daily. Did some lst to the main branch to try and keep the tops at even height and share the light. AH is still now flowering at day 49, I've been checking her stems and no sign of pollen sacs so I'll be patient and try not wig. She's a little monster now only put on 5cm in height this week but has so many more flower sights than the BB so🤞🏼 she flowers. If she hasn't staterd by next week I'll try and work out another light and space and switch her to 12/12 incase it's not an auto. Both plants have shown some purple on the new leave stems after mid week watering. I think the pH is too low and causing a lockout. Water went in at 6.6 and runoff was 6 but my pH pen seems to needs re calibration every time I test it and it's inconsistent with my fish keeping pH test kit. I just don't trust it. I'm investing in a better pH pen. Happy growing everyone ✌️🏼