Low flow, lots of light, lots of nitrates. to get rid of it, scoop out what you can, cut light down to half time a for a week, and stock pump in a 29 BC isn't enough. And there is no need to scream.
Check the archives section for ways to cure it.
oh, look at that, i was kind enough to get the thread for you! https://forums.saltwaterfish.com/t/73002/how-to-rid-your-tank-of-red-slime