some one please give me some sensible answers to this prob I am 4 wks into flower with blue cheese am growing in coco 10 litre pots food is canna coco a and b and using big bud i am using the correct measures when adding then i check with my ppm wand and the food sits on 1.6 the leaves have started to turn from lime grn to yellow with a fewspots and then the leaf dies i am very concerned with ph down i am using thought it might b a mag def but used epsom salts to clear this but still the same looked at other pics on this site and the only thing i can think lookin at other pics is that i have a nitrgeon def firsly can my ph do this to my plants then how do i clear the def can i use nitric acid to put nitrigeon bak into the plants or shall i just change the ph down am using ph strips to measure the ph level this to b correct also sitting about 6.o to 6.2 any help please as i am pulling my hair out 
cheers
cheers