My fuge smells gross!

[Amyandlars]

I have a small outbreak of cyano, and I think something must have gone down there and died. It smells like the time I got a dead gorgian in shipment- that nasty rotten flesh smell. I took out about half the macro algae, because it had weird slimey coat and bubbly film on the top. I thinking about taking the rest out, and washing it off with tank water or something to get the rest of the cyano out.

Is this going to mess up my phosphates or nitrates levels up?

Should I temporarily add a powerhead to the fuge to keep the cyano away?