Surface Film

[Snaz]

My line of AIO suffers from this problem. The issue is the overflow not working correctly, water leaves the tank from just under the surface instead of overflowing at the surface. I do not know what overflow you have but take a look at this thread on nano-reef.com and this simple mod solves that surface scum issue in a jiffy.

http://www.nano-reef.com/forums/inde...owtopic=169081