Odd coating

[Istrom]

Hey all, oddly enough this post isn't about my fish, but my tank. It seems to have an odd film on the surface of the water, which isn't allowing many air bubbles to get through, it also let's snails crawl on the underside of the surface of the water! I'm not sure if this is bad, normal, or what. The only thing I've added recently is some brackish salt for my guppies. Any ideas what it is?

 

[Istrom]

Note: it doesn't feel any different than water, and cannot be scooped out. If it weren't for air bubbles and snails, I wouldn't have noticed it at all. Even without snails and bubbles, it's completely clear and looks like just water.

 

[Khuligirl93]

Probably a protein layer caused by insufficient surface agitation. Try lowering your water level just a bit in order to cause a waterfall effect from the filter. I've also heard people say they can get rid of it by placing a paper towel on the surface of the water to soak it up.

 

[Mebbid]

A surface skimmer seems to be the easiest way to get rid of it. Otherwise increased surface agitation should do the trick nicely.