matt...Hey...I had the same thing last week...but never before that. I even had bubbles trapped in the algae. I had been thinking that I needed some more flow so I went & added a 1140 power head (300 GPH) to go with the 960 gph circulation pump drilled into my tank. I was also getting rusty red slime cyano also along with a dead spot of no circulation on one end of my tank. Since I added the power head, the film is GONE...I bought ChemiClean for the red cyano...but it isn't completely gone...but I do see a BIG difference in the water flow.

Also got a sand star to help keep my bed sifted...so we'll see about that one.

It's funny...but it seems lately that a lot of us here in SA are having probs with water quality. I wonder if the ones having probs are without RO/DI's.

Hope this helps - not sure on a nano...since I have a 100 gal.