Looks like dust on the glass.

[Anthonyl]

So I have my 220 Dt with 50g in the sump. Everyday it looks like the glass has a coat of alge. I have a mag cleaner and when I clean the glass it looks like dust. Any ideas?

 

[Anthonyl]

I have 0 ammonia 0 nitrates and 0 nitrites. I have shut off the skimmer and started feeding a bit heavy to hopefully bring up some nutrients and maybe get some better alge growth.