Oil looking grease on top of tank.

Hello
I had this oil looking grease thing on top of my tank since the tank started. When I put my finger int the tank, it spilts. I have 2 powerheads pointing at each other at the tank. 1x750gph and 1x600gph. I will take a picture later during the day. Anybody know how to get rid of it?
Thanks

 

Bloodkip

what you have there are protien based wastes that are held on the water surface by surface tension

this normaly occurs becuase water movement at surface is not adequate to break it up and then deliver this to the skimmer and or filter etc

you can remove it by placing careful a dry paper towel on the surface the white film will stick to the towel you just need to peel it away from surface gently and the oil slick comes with it

then angle one of the power heads more across the top of the tank so there are waves
this stops the film coming back and forming on there again

Steve

 

You need more movement in the water, add some more power heads or maybe try to change the direction of them.

 

Ok, thanks. But what do you mean by angle one of the powerheads more across the tank? Do I point one of the powerheads up?

Currently the 2 powerheads are pointing at each other.

 

yes point one of them slightly upwards , you dont want a jet of water above the water surface
but you want it angled so it pushes water and creates waves which will chop up the surface and prevent film forming

Steve

 

That film is one of the disadvantages of not having a sump with an overflow box that skims the surface. With the amount of flow you would need at the surface to break it up, evaporation will be more of an issue.

 

+1 to all stated above, and why do I hear the TANG POLICE coming. Good luck with your tank

 

Good point,this is how i deal with my 29 gallon(with no sump),i have a powerhead pointed up for not only surface agitation,but to break up the film as well so my skimmer can catch it and keep it in check,buuuuuuut-I top off 3 times as much water in my 29 open top than i do in my 28 closed top nano.But breaking the film up is important to allow proper gas exchange to take place at the surface.