Yellowing/spotted leaves 5 weeks into flowering...

Hi all...1st time grower...1st time posting here.
Ive read a few threads about what this could be.
Everything from being root bound, to spider mites.
Ive checked the leaves both top and bottom...no sign of any bugs
Im growing B.C. Big Bud
Fox Farm Ocean Forest soil
3 1/2 gallon container
PH is at 5.5 (used soil probe)
Veged for 6 weeks under a 400W MH
Flowering now for 5 weeks under two 400W HPS's
Growing in an empty bedroom (not a closet)
Buds look fine and have 30-40% red hairs on them
Using Fox Farm nutes and using the grow guide at the bottom of this page
Marijuana Grow Guide | Soil ....Im on week 11
Should I be worried since theyre only another 2-3 weeks from harvest?

Do you use CalMag or unsulfered molasses as a source of calcium?

Ingoing water ph in a soil grow, (FF Ocean Forest, for instance) should be between 6.3 and 6.8ish.

Best to remove leaf litter before the bugs do take hold.

No calmag or molasses.....
Just the FF nutes (big bloom, grow big, and tiger bloom).
Ive only been adding the nutes every other watering, and a friend said it needs a boost of nutes...
I've read that less is better than too much tho.

Fox Farms has a weekly feeding schedule on their website that's pretty solid. I'd recommend you try following it for a few weeks and see how you like the results. :thumbsup: