General Care Discussion :: Oily water at the surface

[Turtlefriend]

I noticed that the water at the top of the tank looks like it has some oil on it. Is this ok or is that bad and how do i get rid of it. The water is about 2 weeks old now.

[Starchick]

I've heard people refer to that as protein slick, it's probably time for at least a partial water change. It seems to happen when there's leftover food breaking down inside the tank (happened to me when Napoleon was sick and not eating what I gave him). Do you feed in the tank, and do you remove any food they don't eat? Does your filter agitate the surface? Also, do you routinely test your water for ph, nitrates and nitrites and ammonia? If you do that you'll get an idea of how quickly your water is getting mucked up and can make sure you change it often enough.

[Turtlefriend]

I do feed my turtles in their tank but they eat all their food, the filter did not agitate the surface but it is now, and i dont test the water. If i change some of the water, wont the water without the oildy stuff get sucked up becasue the protein slick is only at the top(i think).

[octpusgirl8]

Try using a small bucket or pitcher or something like that to take water out from the top rather than siphoning it out. The slick is an indicator of dirty water so you do need to change some of it, but to remove the existing gunk this should do the trick.

[adam85491]

Aren't there filters called protein skimmers that do exactly that?

[steve]

Protein skimmers are a bit expensive, but I believe this situation is primarily lack of surface agitation. Feeding in the main tank contributes to it. Aside from that, a regular partial water change is a good idea

[DavidY]

Protien skimmers don't work very well on freshwater tanks since the surface tension of freshwater is much lighter than saltwater. And, yes, they can get very expensive (mine cost $350 - for my sw reef tank). They are used mostly in the saltwater hobby.

[Turtlefriend]

So if the surface is just agitated it shouldnt happen?

[Starchick]

For the most part, but you should take it as a warning that you need to clean more often. It's a sign that harmful chemicals are building up in your water.

[DavidY]

Scoop the water out from the surface. It's important to prevent this from happening as the slick will prevent proper gas exchange between the water and the air. This will cause a build up of CO2 and depletion of O2. Also, the nitrifying bacteria in the filter requires large amounts of oxygen. You should always run the return from the filter so that it returns the water to the tank above the water line so it can aerate.