I've had my 90g up and running for a few months now and I've been fighting some sort of algae that I can't seem to beat... or identify. Before setting up my 90 I had a dino outbreak in a 45g that I successfully got rid of by dosing hydrogen peroxide so I tried that again thinking I had dinos but to no avail. I did about a month long stint of the peroxide daily and also tried Vibrant after reading some reviews online. The algae is almost like a sheet of bubbles, is clear for the most part, and is located only on the rock and not the sand bed. I tried not dosing the peroxide for about 10 days, and didn't do much else beside clean the glass once, hoping to see more of the string like algae I saw previously but there was no change to the overall appearance. I've got a ball of chaeto in my sump that's a little bigger than a softball when I compress it together and seems to be doing really well. I've taken an airline tube and siphoned off everything I could a few times while I was dosing peroxide but it just came back. I haven't tried a complete blackout yet, though I did reduce my light period by a few hours. Not currently running GFO as I'm worried it would just be expended in a couple of days. All water is from a brand new BRS 4 stage and the inline TDI meter is showing 0. All parameters are normal including Mg. All corals, all 6 frags is all, are doing really well and don't seem to be bothered by the algae but I'm hesitant to add anymore until I figure out what's going on. Anyone know what I'm dealing with or have some suggestions? Thanks!