What's going on in my tank?

[droidus]

Please see attached image. It is the white moldy-looking substance, not the dots.
It seems to happen when I turn off the lights to control algae growth.

 

[maleks.reef]

Could be some sort of sponge, not sure. I suggest you try to get a better picture with clean glass so that people can help you out

 

[ying yang]

Maybe algae dying off ?

 

[Mxracer65]

Please see attached image. It is the white moldy-looking substance, not the dots.
It seems to happen when I turn off the lights to control algae

Please see attached image. It is the white moldy-looking substance, not the dots.
It seems to happen when I turn off the lights to control algae growth.

It's hard to tell what we are looking at. Most likely sponges.