flow and algae

hi, my tank is experiencing a bloom of cyano and i want to kill it off asap. current parameters: nitrate, phosphate and nitrite are 0, ph 8.2, salinity 1.026.

i read that they grow in low flow areas so i added 2 pumps for flow so now my current flow is 54x the volume of the tank an hour at a total of 3000gph. i got 1 jebao wp-25 on the front for coral flow, 2 250gph pumps on each side to pump the back of the rocks, and my return pump for gas exchange pointing slightly up but also hitting rock. ive also replaced my bulbs about a week ago. 2 blue 1 coral plus and purple. i also run carbon and gfo. so everything seems fine to me, so why do i have this algae???

thanks!