ph 6 and lockout

is a ph of 6 consistantly enough to cause a ca lockout i keep having an issue with what presents its self as a ca issue(i use calmax) but seems to concentrate within the foot print of the light the growth outside of the immediate foot print show no signs i have a sealed aircooled hood with a fan over the tops 400w 13in above the canopy is it possible my reflector is hyper efficient at focusing light and creating a huge hot spot as i show no other signs of cal deficiency strong branches normal growth no root issues im stumped any insight or experiences with this issue welcomed

6.0 is good for mid to late flower but not for early flower or veg. 5.6-5.8 is better.

im in week six flower always ph to six but my temps are good at 65-68f at night 75-80f in the day ultra low rh however i feed at relatively low doses about 65% of full strenght per the bottles leaves arent crispy dont think its nute burn