Number 1 lower feeding. Number 2 try a 3 day black out. Ut the lights and throw some towels onto the tank after a large water change. Need to get the nutrients out so it has nothing to feed on. Looks like some cyano and caulerpa. Heavy skimming with a protean skimmer. Lots of water changes. Try to manually remove everything you can. Like wow haha. Just pull as much out with a sand vacuum and your hands. Try blasting it off with a turkey baster. Add some carbon to your sump or filtration. Different types of tangs could help depending on your system size. Urchin, conch snail, some types of blennys.
#reefsquad #algea maybe someone else can shed some light. I’m still new to hobby but I’ll try to help any way i can!