Same here, I spray about 20 min or so after lights on. I’m using led though not sure if it’s because of hps but don’t think so. Pretty sure Doc uses double ended hps at any rate. I spray Brix every 8-10 days @ 1ml less than suggested. So I mix 7ml of Brix foliar with 8oz water... I’m only spraying one plant in veg and one in flower. Maybe you’re spraying too heavy and it’s leaving too much on the leaves? That’s the only thing that comes to mind.