White North health issue

[cruisingrobin]

I have been growing about a year and all has been good until now. Even these are doing not bad but trouble is lurking.
The issue runs across all 4 strains Health Canada seed, Budda Bud, BC Kush and Kush
Both on my Veg and bloom plants have been developing dark patches on the leaves and yellowing of the lower ones. please excuse pict. The lower leaves in particular.I also believe that I have over watered the last week



Growing in Pro Mix with a varied combination of induction and hpi light
They have just had 2 feedings of the DNF 50%, and one tbl spn of epson salts per gallon.

Nutrient is Dutch Formula A&B at 50%, PH, 5.7 75F temp

 

[JJ Bones]

When is the last time you flushed? I find flushes tend to be like restarting a computer. They fix things more often then not.