[unclejed]

I have used glass tops for all the 20+ years I've been at this. I am not sure why some find it hard to believe. If you have a sump, that is where you get your evaporation and gas exchange along with the protein skimmer and surface (main tank) agitation from return flow and power heads. Like I said earlier, diatoms will come and go. Try redirecting the flow and if you don't have filter floss in the chamber where your bio balls or live rock rubble (whatever you have) try putting the floss/pad on top of the rock/bio balls. Then remember to change that weekly.