What is this

[305mclovin]

[DW2]

Howdy 305mclovin, What does the under side of the leaves look like (possibility of bugs)? What is the growing environment, growing media, air and or water temperatures, nutrients, and how old are the plants?
It could be one of (or combination of) many different causes, pH imbalance, nutrient deficiency, or bug infestation. More information is needed in order to make a S.W.A.G.(scientific wild assed guess! LOL).

[starramus]

Under magnification looks like aphids, but plant could have additional problems. Try this https://homeguides.sfgate.com/dawn-d...ent-82536.html

[305mclovin]

Dwc water temp 72° coco coir and pearlite 6th week of flower nutes fox farm trio and cal-mag ppm around 1250. Ph 5.8 grow tent 7x7 rh around 55 room temp 72_79
250 watt led full spec at 18 inches from canopy
looked under 40x and 60x didn't see any bugs

[305mclovin]

Also this

[9fingerleafs]

looks to me like calcium toxicity