Oily water surface

[Aqualux]

Not quite sure where to post this but here we go anyway: ever since I set up my tank last week the water surface has been covered by an oily film that doesn't seem to go away.
I encountered this problem in previous set-ups as well. Now, I know the usual techniques recommended to get rid of such a film (moving the water surface, sweeping it off with kitchen paper) but I have previously tried these and the film always returns.
I remember reading that it might be related to some bacterial activity but I was wondering whether any one here has encountered the same problem and whether there might be a permanent solution.

Cheers,
Yves

[XPLOSV]

Give surface skimmer ago.

[Aqualux]

Thanks for the tip XPLOSV but I knew of that one before as well. The thing is that my tank is quite small and I don't like the idea of installing a skimmer which will take up more space.
Further, installing the skimmer will not really get rid of the root cause of the problem...the questions on my mind is still: what leads to this kind of water surface?

[XPLOSV]

Might come from fish food, equipment (filter/media), your hands, dead fish (maybe) and air that carried oil (not sure how to explain this).

I'm sure there are some other factors can caused this issue as well.

If you are using a hang on filter see the url below it also come with a small skimmer.
Age of Aquariums - Supreme Aqua Bio Filter ( 350lph )

[XPLOSV]

You might be able to use this as well.

ADA Clear Float

[Raslad]

I had this problem with a certain sand I was using. I rinsed it out, but it still clouded the water BAD and left an oily film on the top for about a week.

[Shadow]

Put some guppy or molly, they will eat it.

[Shadow]

Originally Posted by XPLOSV

If you are using a hang on filter see the url below it also come with a small skimmer.
Age of Aquariums - Supreme Aqua Bio Filter ( 350lph )

Try similar product (different brand) but doesn't seems to work. I thing the problem is because I do not have control over the flow. Thus the top inlet doesn't suck any surface oil. Not sure if other also have the same problem.

[XPLOSV]

I think to get to the bottom of the issue is to make a check list of all the things you use or have contact with this tank this way you won't miss anything.

Check and clean each items on the list properly.
Making sure every thing is clean or even cover up the tank from exposing to outside air and monitor.

My tanks also get this when I feed Tetrabits.

I don't think you can eliminate it 100%.

[XPLOSV]

Robert - the skimmer part can be adjust according to the water level.

[Aqualux]

Thanks guys for your inputs. In terms of eliminating causes:

1. Dead fish: I can excluded that for sure, the tank is a week old.
2. Hands: don't think so, I pay attention to having them clean before working in the tank.
3. Fish food: unlikely, the film was there before there were any fish, thus no feeding at all.
4. Filter/media: possibly, although I only use coarse and fine filter wadding plus ceramic filter medium (Eheim Mech).

By the way, my tank is not an open tank, thus always covered.

Overall, I am still mystified...any other insights?

[XPLOSV]

Sorry, I'm out of ideas mate as I don't see much of this stuff in my tanks.

Let me know when you crack this case.
I'm interested to know where it come from.

btw: should the tank silicon have any thing to do with this you think?

[Shadow]

is it planted tank? because if I'm not mistaken plant do generate those surface protein during photosynthesis

[Aqualux]

I would also pretty much rule out the tank silicone. The tank is about 15 years old thus the silicone should no longer have any such effect.

Yes it is a planted tank and I suspect that it could be somehow related to that...I never had that problem when the tank wasn't planted properly.
Also I cannot rule out the sand but it's been in there for over a year as well by now...

[XPLOSV]

Can you post a picture of this tank?

[Shadow]

Confirm because of the plants then. It is normal, nothing to be worry about. If you do not have space for surface skimmer, any surface dweller fish should eat it (e.g. guppy, black molly, endler, etc)

[blue33]

Originally Posted by Shadow

Try similar product (different brand) but doesn't seems to work. I thing the problem is because I do not have control over the flow. Thus the top inlet doesn't suck any surface oil. Not sure if other also have the same problem.

It works! You just have to seal(80%) up the bottom inlet suction by 80%, then the surface skimmer will suck in more aggressively. It works for me. Was taught by a LFS.

[Rudi Giacomini]

Hi
If the oil surface is similar to the one in the first picture at this address
http://aquatek.blogspot.com/2008/03/quinta-e-sesta-settimana.html
all you need is to put more oxygen in you tank (simply changing the jump of water coming back from filter).
Mainly oily films are due to bacterial explosions on the surface...

[Aqualux]

Thanks for the continued input guys!

@ EXPLOSV: would post some pictures soon, probably over the weekend.

@ Shadow: I am not quite sure if I can draw conclusions that soon but it is one of the likely options anyways. When it comes to the surface dwellers, they may do the job but they don't really fit my plans for the tank, I don't intend to buy any.

@ Rudi: you confirm what I suspected, that the film is due to bacteria on the surface. By the way, I was aware of the trick to disturb the water surface to break the film. So far, I didn't do it for two reasons: firstly, I didn't want to drive any of the CO2 out of the water. Secondly, the pipe through which the water returns is fixed thus that I can only lower the water surface to achieve the same result. I may have to experiment to see how much lower I can go before the water line becomes visible under the tank cover.

[Rudi Giacomini]

Originally Posted by Aqualux

Thanks for the continued input guys!

@ Rudi: you confirm what I suspected, that the film is due to bacteria on the surface. By the way, I was aware of the trick to disturb the water surface to break the film. So far, I didn't do it for two reasons: firstly, I didn't want to drive any of the CO2 out of the water. Secondly, the pipe through which the water returns is fixed thus that I can only lower the water surface to achieve the same result. I may have to experiment to see how much lower I can go before the water line becomes visible under the tank cover.

Ok. Bacteria films are tipical in new, or rearranged, tanks and are due to a non stable enviroment. Generally they are gone in 2-4 weeks but we can decrease that time using some tricks.
You has to keep in mind that oily film is not dangerous but reduce gas exchange in water surface so it's suggested to break it with water flow. This drive out CO2 as you point but it's sometime necessary because in these conditions you are going to have to low oxigen.

Another thing that work is to make more frequents water changes and to get out the water with a glass from the surface (so you can get out part of oily film). Keep in main that removing film is not the solution, You need to reach equilibrium in enviroment to solve problem.

So another thing that work is to improve water quality and wait. Every one of us should keep in main that those biological phenemona are a natural part of start up cicle and averything should go at the end of first month.

In my case (the pictures You have seen) I made a very slow and very natural startup that requires me two month...but that is my way... very slowly :-)

In Your case I think you don't have to worry to much for CO2 for some days and try to put more oxygen in water as I stated before. Only some days...