Strawberry Cough 4x4 Indoor, 480w LED

At week 8 of Veg, I had topped twice and I took about 10 clones out of the tops and bottom branches*. Then I put these 2 outside to strengthen up with the wind and a bit of partial sunlight and get used to 12-12. They spent 2 weeks outside, which was not such a good idea cause they caught spidermites & powderly mildew. My ppm/ph meter broke and I had to order a couple cheaper ones and and spares, when it arrived, the runoff was at 2400 ppms! -- flushed with lots and lots of 700ppms water and used the runoff on a lemon tree. I started to notice a P deficiency, it was hard to diagnose because I started out reading and everywhere they say it is most probably the strain, but in fact it didn't show this in the last crop, so I added up PK just 1.5ml. It didn't seem to fix the issue.