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inkevnito

Oily film on surface... AGAIN!

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Hellooo,

Yet another problem with the oily film..
Last time it kept coming back and so i thought i would do a whole tank rescape and clean. 

- No oily foods were being fed
- Nothing changed besides addition of purigen and new filter floss in canister. (This was a few months ago)
- livestock is corydora, shrimp and betta.


During rescape and clean, i washed inside of canister, bio media and tubing with boiling water, and h202. Scrubbed tank clean and dried in sun. 
Reassembled filter with new filter floss and the boiled bio media to start everything fresh.. with the addition of mature media from another tank.

Tank was set up on 24 september, and has been progressively building up oil, till this week its thick again with a shine of rainbow!

I know surface agitation breaks it, BUT i would like to know the cause of this as all my other tanks dont have this oil slick. Only difference on this tank is livestock, filter and filter floss.
Ive narrowed it down to MAYBE being filter floss, but i have used the same brand/type for 3 years now.... 


Also a note to add, when i run fresh filter floss under the tap, the water slides off as if its coated with waterproof stuff, it doesnt absorb any water. 


Thanks in advanced!!

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The film you are seeing is almost certainly a protein scum that is a produced by bacteria (sometimes in association with algae). Its not oil, even though it behaves a bit like oil.  The film is not toxic but it does hinder gas exchange at the water surface.

Two options.

1) good tank hygiene will win out in the end as the tank matures.  The film is symptomatic of an imbalance, but as biofilms and beneficial bacteria develop in the filter and on surfaces in the tank the film tends to go away on its own.  Your rigorous cleaning to remove the "oil" is potentially holding back this maturation process.

2) I install a skimmer as a temporary fix.  I personally like the eheim skim 350.  You can put the skimmer in for a week and it will disrupt the layer (actually pushing the film into the water column where it gets taken out by your filter).  After a week you can often remove the skimmer and the film will not return.. for a while or perhaps not at all.  I sometimes get a film on a mature tank but its generally caused by me over feeding or over fertilising.  In which case I just bung the skimmer back in for a week and do a water change and its fixed.  IMO a skimmer in the cupboard is a useful tool to have.  Some people keep them in all the time but I find they do trap shrimp and fish and require my attention to keep clean so I only use them when needed.

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Thanks @Grubs for the response. Before the rescape, i had the oils for a good 2 months, i would have thought it'd mature during that time but didnt. 
I think i have the Ocean Free skimmer that i use which works a charm, but just wanting to find the cause. 
I waterchange once a week still, like usual and just scrub front and sides of tank leaving back. 
I'll try and let the tank mature again as it just started fresh and see how things go. I dont mind having the film there, but its driving me crazy because i cant find the source of it :x 

Thanks again, i'll keep this updated in a few weeks or however long it needs to mature. 

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The big problem with floating oily protein waste is that its able to stay out of the mouths of the sticky bacteria that are inside the filters. Using overflows will surface skim, as will surface skimmers. Another trick is to add clay treatments such as easylife. Its a short term fix though. As the aquarium microbe communities mature, this usually becomes much less of a problem. Most of us focus solely on bacteria, but its often larger creatures living in the water that are consuming it. A good way to inoculate a new aquarium with these mature style critters is to add water to it from healthy tanks. This way we bring in the solution. As with all biological controls, its not an instant effect, rather a process where the food source is reduced slowly until it gets in balance with the things grazing it. This is very similar to how mature aquariums have large quantities of diatomeous algae eating critters and so dont have diatomeous blooms. I mean it tries to bloom lol but theres so many things eating it, it never gets out of control. Get enough cows in a paddock and you wont have a problem with long grass, no matter how much it wants to grow :D

 

So yea you have other tanks with no oily film problems. My suggestion is to add some water from those tanks, to the problem tank. In the hope of introducing the solution in the form of some microbe that loves to feast on oily film! 

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Is it a fairly new tank? I had this a few years ago when I bought a tank from a fellow who made his own tanks. 

I found out months later, he wasn't using the right silicon for tanks and it was leaching into the water. It became a big deal at the time and the silicon company came out

to check it out and after doing tests admitted it was the silicon and compensated me for the tank and the loss of fish.

Since that time I have been very selective where I buy my tanks.

I am not suggesting that this is your problem but people should be aware of who and where they buy there tanks.

Hope you solve your problem.

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Thanks for the info,@Sueley. Im using 2 of these tanks and only one has the problem. I tried adding mature water from that second tank into this tank as suggested above and its working.. BioAid just came in the mail today also, but i might save that for another day and see how this works out first. 

 

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