Phosguard works great for me, doesn’t completely strip out all my phosphates but keeps them really lowNeed to get phosphates down and the cyano will go away. You can blow it off and scoop/suck it out.
Just for the record, I dont really care for chemiclean. It does work, just needs a ton of aeration and the skimmer will overflow the entire time. Unless the issue is corrected, it will just come back.