Algae Die-Off

[SurfTrack]

I am having weird massive blotches of green algae die off on my rocks in short periods of time (a couple days). What could be causing this? I have been doing a decent amount of water changes recently, could just the plain export of nutrients have caused it?

Here are two images, one of a normal rock and one of the area with the white blotches. (BTW this is not dead coralline.)

 

[Brad Miller]

I get white spots on my rocks when some of it flakes off or the cleanup crew suck it clean, don’t know if that’s what’s happening to yours or not