Tiny bubble on top of my tank...

[ogredawg19]

For the last couple of days the top of my tank doesn't look right. There's tons of tiny bubbles and also it looks like it has very thin layer of oil or something. I think the bubbles are being produced by my protein skimmer (I have a cpr bakpak 2), but is it normal that the bubble stays and doesn't pop. I don't have any current coming from the top, so is that something I should have?

 

[dantodd]

I suspect that you aren't skimming the surface of the water. If you don't have an overflow or surface skimming drain then you will get a lot of oils etc. building up on the surface of the water. This increases the surface tension and decreases the water/gas exchange. Since you have a skimmer your probably still have plenty of oxygen in the tank but the increase surface tension can prevent air bubbles from popping.

You can often alleviate the problem by pointing a ph at the surface to mix the oils etc. back into the water column where your skimmer can remove them.