That'd knock it back some, but it will mostly likely return as its in your water column as well. A toothbrush and siphon worked well for me when I had it on my rocks. Id start with the easiest treatment first, a 3 day blackout and heavy skimming during that time.I had to empty my skimmer 2x a day once it started dying off. I've eased back into my water changes and stop dosing trace elements as I read that can feed dino's and cause outbreaks, but there seems to be mixed opinions on whether that's true or false.
Also Vitamin C dosing constantly brought them back in my nano.
This last time they popped up in my fuge with some cyanobacteria. I killed the fuge light and it popped up in my display. So if it were me I'd do the whole tank at once. After 3 days ease back into you light schedule and see if it comes back.