what line of nutes are you using at the moment, and at what doses(per gallon)? you burned them up with something for sure.
its a phosphorus burn, cut down your nutes to 15ml per gallon. you just want the nutes to be present in your soil for the roots to take in, giving them full doses doesnt really make that much of a change,especially the boost. burnt tips is an indicator that youre using a strong dosage of nutes. goodluck man. stay lifted.I've maybe nute burn so I gave them a flush , now back on 25ml a&b 20ml rhyzotonic 20ml boost , on other leaves there are few burnt tips but theses leaves look somthing totally diffrent