i have a 72 gallon tank every thing is great except for light thin film on surface of water...
any suggestions....remains even after multiple water changes
Its the fine dust & oil films. Get a surface skimmer to skim it off the surface, else, it's going to block the effectiveness of your lights. Quick fix - use a fine mesh net to scoop them up and wash up the net after each scoop, or pick them up using dry paper towels (you will be wasting lots of them though)
I used a powerhead pointed a little high to keep the water turbulant. That reduced it alot. I was told that it was bacteria. I know that it isn't good for oxygen exchange...
It is not bacteria. It is disolved organics that your skimmer is not getting to because it is collecting on the surface of the water. You need a surface skimmer as well as pointing power heads towards the surface of the water to break it up.
