# Oil slick



## RJSimoneaux (Jan 2, 2006)

what causes the oil slick on top of my tanks?

What is the best way to get rid of it?


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## raven_wilde (Nov 16, 2005)

I usually only get oil slicks on my tanks when something has died, particularly apple snails that have a tendency to crawl way into the rockwork and expire. In this case the only thing you can really do is dig out the carcass- or what's left, and if it's really bad try some new carbon in your filter.
With my turtles, I tend to get oil slicks when I feed a lot of frozen or live foods, so that could be your problem too. Usually when there is something odd happening in my tank, it's do to something I put in there, so look at that first, what have you been putting in your tank lately that's different?


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## John N. (Dec 11, 2005)

I often wonder what causes this myself. It's possible excess food or rather maybe something else...

The best way to get rid of it is surface aggitation, or using a good paper towel and placing it on top of the water to soak it up. Of course it will return after a while...

-John N.


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## magicmagni (Aug 19, 2004)

I'm betting you don't have any surface agitation. It's probably not a bad idea to have the spraybar or filter outlet just below the surface to make gentle ripples on the surface of the water. Not only will doing this remove/ reduce the oil slick but will also aerate the water, which gets plants pearling sooner and fish breathing easier. The latter may also allow you to run higher concentrations of Co2 without harming your fish. You may loose a little Co2 with surface movement, but I think the benefits outweigh the little bit of Co2 you loose.


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## Raul-7 (Feb 4, 2004)

I believe it is caused by excess protein and organics - probably overfeeding. What I noticed is that by aerating via an air pump it actually forms lipid bubbles and as they pop you can actually see the protein just drop into the water column; the fish seem to like eating too.


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## RJSimoneaux (Jan 2, 2006)

*Oil Slick*

Thanks guys and gals,

Do not think I have any thing dying. Over feeding is not a problem. I have always kept corys to prevent that from happening. Most times food consumed in a few minutes.

I was wondering if a tank's gravel could foster some sort of slick? Thats the only thing I can think of. or could it be something in the fish food?


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## trenac (Jul 16, 2004)

Using a surface skimmer or adding Molly's to your tank will take care of the surface scum.


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## jsenske (Mar 15, 2004)

ADA Lily Pipes are designed specifically to deal with this problem. If youare interested, you can see them here: www.aquariumdesigngroup.com click on the "shop" link at the top and go to: Filtration>Lily Pipes


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## JaySilverman (Jun 19, 2005)

I belive its actually from tap water. I don't over feed at all and nothing has died. I think its proteins and such. Its not really harmfull and simple surface agitation should get rid of it.


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## longspeak (Dec 20, 2005)

*Surface Skimmer*

Is there a recommended surface skimmer?


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## magicmagni (Aug 19, 2004)

Eheim makes one, but IMHO one just needs to set up their filter outlets properly with a lilly pipe or spraybar or whatever it takes to get some surface movement. Save your money for more plants and fish. They tend to look nicer anyways


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## Raul-7 (Feb 4, 2004)

What I noticed is that you actually need something that "interrupts" or breaks the surface of the water to completely get rid of it; something like a BIO-wheel, surface skimmer or overflow. The reason being, I currently run my spraybar and powerhead towards the surface, yet there's still a noticeable layer; meanwhile if I add a BIO-wheel or an air pump, it disappears.


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## birdman (Feb 25, 2006)

it also could be phosphates is your tank or tap water.


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## tomas110011 (Jul 25, 2005)

I have a oily film on my 6x2 tank setup last week and im sure its not from overfeeding cause I haven't put any food in it at all.

I have been crushing lots of little snails though and leaving them in there. I think thats the answer. Runnig a air stone at night eliminates this problem for most of the next day.


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## RJSimoneaux (Jan 2, 2006)

birdman said:


> it also could be phosphates is your tank or tap water.


Thanks Birdman,

Thats one that probably applies to me. If you do not mind me asking. How did you come by this knowledge?

To the others that answered about surface agiation and skimmers.

I agree that surface disturbance helps it, and has temporary releaved the problem. In the 100gal I use a Eheim surface skimmer and I am very happy with it, except for the price.

What I really wanted to know is what were the cause/s. Prevention is what I was after. At first all I had heard about was excess protiens. I been doing the aquarium thing for 41 years and do not think I had any dead or dying things in the tank and was searching for other reasons. Always looking to learn. Thats why it is still fun for me.

TIA:wink:


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## Alexk3954 (Jan 2, 2006)

I have heard that mollys will clean the surface of the water, but I have not personally tried it...


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## pineapple (May 4, 2004)

For reasons not clear to me, no pun intended, in my experience increasing either the posphate dosing or the potassium (K2SO4) dosing eradicates the slick. Experiment.


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## IUnknown (Feb 24, 2004)

The owner of aquaforest told me that the oil comes from the C02. He said that the ada Co2 is designed to reduce the problem. Don't know if it's true, but I thought it was interesting.


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## AaronT (Apr 26, 2004)

Alexk3954 said:


> I have heard that mollys will clean the surface of the water, but I have not personally tried it...


This is true. If you don't want mollies in your tank all of the surface aggitation techniques mentioned will also do the trick.


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## magicmagni (Aug 19, 2004)

IUnknown said:


> The owner of aquaforest told me that the oil comes from the C02. He said that the ada Co2 is designed to reduce the problem. Don't know if it's true, but I thought it was interesting.


Interesting thought. Perhaps being caused from slight impurities?


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## Bert H (Mar 2, 2004)

Along with mollies, platies, and guppies will also help keep it down.



> in my experience increasing either the posphate dosing or the potassion (K2SO4) dosing eradicates the slick. Experiment.


Somewhere in the rusty hinges of my memory I seem to recall reading this myself as well. I think it was phosphates, not potassium.


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## Biowf (Nov 1, 2007)

Just a note that after battling a surface oil slick for a few months in my newly set up live plant tank (skimming it, paper toweling it, making sure it was not decay) I finally found this forum and this thread. I happen to have another tank that is packed with mollies. So I moved a few over, went to pick up my daughter from school, and a little over an hour later the water surface was clean!!! So thank you!!! and yes this method works great (at least in my situation).


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## Bert H (Mar 2, 2004)

Glad to hear it worked for you! And welcome to apc.


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