Please explain this problem

[Jyetman]

I have what looks like red slime that grows under corals zoos, yellow polyps, and GSP even mushrooms. Its killed a fast growing colony of zoos took it over even turkey baster doesn't work polyps fly off. I've started doing small water changes daily for six or seven months now about six cups worth. The problem is since these small water changes coral growth slowed and a thriving colony of pulsing xenia has withered away what once was years of fast growing bushes now slowly melting away. Candy canes same don't expand fully but blastos doing great? The red slime grows faster then ever not even dented. What is going on there are no dead spots the slime grows even in high turbulent areas? When I test for PO4 and nitrates all zero. Macro algae and a small algae scrubber grows at steady rates. Not sure what to do anymore stupid snails don't touch it.

 

[xanthurum]

Is it cyano? If it is there are lots of things you can do but you have to identify if that's it first. If it isn't then you need to figure out what it is to find a solution. Doing such frequent water changes is likely the cause of the corals doing poorly. All the corals you listed actually do better in water that isn't so clean.

 

[Jyetman]

Is it cyano? If it is there are lots of things you can do but you have to identify if that's it first. If it isn't then you need to figure out what it is to find a solution. Doing such frequent water changes is likely the cause of the corals doing poorly. All the corals you listed actually do better in water that isn't so clean.

How do I identify it looks like stringy red slime. If cyano or algae not sure according to internet searches looks like cyano? When I blow it off corals and rocks it comes off easy floats around in flat patches always try and catch what I can with a net but grows back quick. I know lighting isn't a factor it grows under corals and shaded areas.