Cannot get rid of cyano!

[MarkoD]

Showed up about a month and half ago.

I have:

Physically removed it by blowing it off the rocks and vacuuming it off the sand. comes back within 3 days to cover everything again.

Been running GFO inside of a reactor

Ive got through 2 large bottles of fozdown

Did a water change.

removed the sump and fuge and completely cleaned them and reinstalled them.

i dont know what else to do, i dont think going lights out for a few days is an option.

anyone have any suggestions