Yellow patches with brown spots. HELP!

I have yellow and brown spots on my leaves. Just did a flush 5days ago. Have been battling white flies but dont suspect that to be the problem. Plants are in two seperate rooms both rooms have the problem. I feed nutes as instructed every third feeding. any suggestions would help.

looks like mag. deficiency

been using pura vida grow 6-4-3. I did just do that flush with water 5 days ago and the feeding four days before that was just water aswell. I guess it could be a mag deficiency.

get some cal-mag+ it will increase bud density as well as cure any deficiency

OK. Ive noticed that the spread of the problem has slowed drastically since the last nutes feeding two days ago. Ive noticed the only difference between my Grow nutes and bloom nutes is less nitrogen. Will I be fine adding cal mag with my current nutes?