# oil film on surface



## markl323 (Mar 21, 2006)

there is always a layer of oil on the surface of my tank. i remove them with 10-20 glasses of water and 1 hour later it is back, covering about 90% of the tank. 

is it safe to ignore this? my tank is 75G and the surface current is generated by an Eihem (rated for 92G) and a small Powerhead.

if not what is the best way? surface skimmer or Mollies/Platies/Swordtails? Thanks!


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## Bryeman (Aug 24, 2009)

This is a protein film and is generally safe except if it's heavy enough to completely cover the surface, which causes poor gas exchange. I can tell you that on all of the planted tanks I've had, this has generally disappeared after a few weeks, but your situation could be different. I skim this off daily by hand using a milk jug and only try to remove the top layer of protein. I know that if you provide enough surface agitation, you can keep this away as well, but then you run the risk of losing your CO2. I have no experience using a protein skimmer so can't answer that.


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## bosmahe1 (May 14, 2005)

I used to get surface film. I didn't care to install a surface skimmer because of evaporation issues with an open top tank. So, I increased the surface agitation coming from the filter. I sacrifice a little CO2 but I probably don't lose as much light penetration either. I guess its one of those trade offs. I have to exchange co2 bottles more often but I don't have to try an suck up surface film during water changes anymore. Perhaps, the fish get more oxygen as well.


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## armedbiggiet (May 6, 2006)

If that is too heavy and not in a normal way than sometime it have to do with what ever you have in your tank... what kinda of sub. do you use?


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## crandf (Jan 28, 2005)

I had the same problem, then I bought a black molly last week and it ate up all the film within a day. Supposedly some other species can do the job too, eg blue eyed rice fish, other mollies, I'm not sure which exactly.


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## markl323 (Mar 21, 2006)

Bryeman, i was thinking of a surface skimmer such as this one:

http://www.bigalsonline.com/StoreCa...y=surface+skimmer&queryType=0&hits=12&offset=

but i'm a bit concerned about the noise level and it makes look the tank a bit more messy.

armedbiggiet, substrate is half Flourite, half sand (look like beach sand). they are not mixed, however. there's also a big Malaysian driftwood in the tank.

i got 2 Black Mollies and they did an OK job but they were also pulling the HC out of the substrate. i think i'm gonna try getting some Swordtails or Platies before getting the skimmer.


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## Bryeman (Aug 24, 2009)

I have no experience with the skimmers, so I can't help with that. I know surface aggitation will clear it up as has been discussed. Either has to be done with your filter outlet, skimmer, or some other method. Hopefully the swordtails clear it up. I've never tried that.


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## armedbiggiet (May 6, 2006)

markl323 said:


> Bryeman, i was thinking of a surface skimmer such as this one:
> 
> http://www.bigalsonline.com/StoreCa...y=surface+skimmer&queryType=0&hits=12&offset=
> 
> ...


I see than it is not the sub. just your tank than... and that surface skimmer would do a good job. Eaiser that way...I just don't like mollies!!:wacko:


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