New strain and some new problems

I started growing m39(i think) clones that were given to me and after a long while of flowering some leaves are curling to the left or right with one side of the main vein yellowing.

I dont seem to have a green thumb as during my last grow the tips of leaves were yellowing with yellow/brown spots and older leaves would yellow and die. Maybe the same problem is affecting this strain in a different way, i'm not sure.

My belief is that my nutrient strength is not correct and that it must be too low. I am going to flush the nute solution today and reset it at a strength of 800ppm. I have some info i found on the net that states in full bloom ppm should be around 750-950ppm. I thought i would start off low and work my way up.

Grow Info:
dwc hydro under 430w hps
my pH is between 5.2 and 6
700ppm GH nutes at a 1-2-3 (G-M-B) ratio

First off your ph is out, you should be aiming for 5.5 -6.2, 5.8 is great. Second you could be getting nute burn and deficiencies at the same time. If you mix the 3 part nute together and get it wrong at all then you could have too high of a concentration of nitrogen with a low concentration of phosphorous.

it was caused by mites