Double Cheese

I think I've had a Phosphorus deficiency going on for a while now. I really started to notice the purple stems about a week ago. There has been a lot of under growth dying and falling away. The Canuk Cheese seems to be taking it the hardest out of the two. It seems the Dinafem Blue Cheese is farther ahead in maturity, she has about 50-60% brown pistils and I am starting to notice the odd amber trich... I don't think she will go another week. The Cheese however, is probably more like 7-12 days out and I'd really like to try and turn her around and get the most out of my harvest. I think I am just going to call this my flush period for the Blue Cheese and prepare for harvest. I've flushed both plants last night with 3x5g PH stable water until my run off tests resembled the water going in. The coco seemed to be alkaline when I used my three-way meter and acidic when I tested using the PH strips, so I'm not sure WTF is going on exactly. I tend to trust the strips more than the crappy 3-way meter. So, it seems I have my coco back in the mid 6 PH range somewhere. I am buying a proper PH and EC meter this week, so any brand recommendations are welcomed! There seems to be a LOT of crap out there and I'd like to only have to buy these once lol. Any advice on what exactly is going on and the best course of action would be appreciated! 👊