# Oil on water surface



## khalidkang (Sep 4, 2013)

I notice there's always a layer of oil on the water surface of my tank. After removing the oil, it usually takes about a day before the oil is noticeable again. How do I stop the oil from coming back again and again?


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## jrman83 (Jul 9, 2010)

Does it have color or is it white looking? If it has the colors then this is the stuff you should be concerned about. The white looking film on top of the water is just bio-film and normal. Increasing surface agitation will keep it from forming.


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## khalidkang (Sep 4, 2013)

Its white looking. Should I just leave it alone, or remove it every few days? I'm using a HOB filter, so there isn't much surface agitation.


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## jrman83 (Jul 9, 2010)

Depends on you. It's normal and does not indicate something is wrong. No need to do anything about it.


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## 20gallonplanted (Oct 28, 2013)

ihave a rainbow colored oil on mine is that bad???


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## shadesofviolet (Sep 21, 2011)

a coloured oil can be from a few different things, but I can't think of any that are completely safe. Skin oils, lotions, some cooking oils, motor oil, gasoline, certain cleaners... they can all cause a "rainbow" effect and vary in the amount of danger. I would clean my syphon, and start doing 10% water changes 2-3 times a day, always cleaning the syphon after. And maybe rinse your filter media as well just incase its something in there?


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## jrman83 (Jul 9, 2010)

Yeah, I'd do a water change but with a min 25% though. I have had it myself from sticking my arms in my tanks. Usually nothing too terrible to worry about, but you don't want to leave. Minor exposure to some things may cause no harm, but prolonged exposure may be different.


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## henningc (Apr 17, 2013)

Depending on your water source you could be looking at mineral content. If your city or town water comes from wells, one quick call to the water department will let you know, then it is likely minerals. That would explain the leaching out of additional substance. A purifer will work, but some stuff will leach out with time regardless.


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## Chang Cindy (Sep 17, 2013)

It's normal you can just let it alone


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