Trouble in flowering paradise

This is my 3rd week of flowering. Today, I've noticed there is some discoloration on her leaves; and it's quite a few of them. Pics are attached. They're under 400w hps, being fed the FF trio, in FFOF (3 gallon pot) and pH is between 6.4-6.8 when being watered.

I'm a little worried. Granted, bud production seems fine; but something is definitely wrong. I originally thought calcium deficiency but idk as this is my first grow in a while. Should I flush her? Any suggestions? Thanks.

I do believe that is a phosphorus deficiency not calcium. Calcium deficiency is tiny little brown dots.

Any other takes?

looks over fertilized and calcium def

the fox farm nutes are low on my list of preferred nutes...and theyre low in calcium

id water with calmag and Epsom salt only

10mls calmag and 1/4 tsp Epsom salt for the next 3 waterings

then cut the calmag back to 5mls per gallon each time you fertilize and 1/4 tsp Epsom 1x per week top dress

and lower the amount of the foxfarm nutes in your future
an appropriate amount might be something like 5mls per gallon of each