What's Up With These Please?

hi all been growing some dp brainstorm femed at week 3 of 12/12
and i have started to get these yellowy spots on some of my leaves
any idesa guys im growing in soil under a 400w hps i have plenty of air flow and arnt sure. ive treated for spidermite ,but cant seem to actually see any pests. ive have been a bit too generous with the watering but i know know and arnt watering as often,the light height is ok about 12 inches away with a fan pc cooling the lamp .
at a loss any advise much appreciated

yo olliedog, looks like the plants are nice and healthy. have you been foliar feeding them? or has there been water or nutrient splashing on the leaves? looks like the light burned the spots where the water collected on the leaves. if you are going to foliar feed them make sure you do it when the lights go out. and be careful when watering, don't get the water on the leaves. that's my guess, it's happened to me too. peace and good luck