# Oily film on water surface.



## si walker (11 May 2022)

Hi all.
For quite some time now I have had an oily surface on the surface of my water. It is persistent. I have tried several things to minimise such as surface movement, paper towel, large water change's etc. It's not linked to my hands either. In about a day or two it's back.
Got any ideas. Let me know.
Thanks!


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## seedoubleyou (11 May 2022)

It’s just a build up or protein’s and bacteria mate, it’s harmless and shrimp like eating it.
Buy yourself a surface skimmer if you want rid of it.


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## GHNelson (11 May 2022)

seedoubleyou said:


> It’s just a build up or protein’s and bacteria mate, it’s harmless and shrimp like eating it.
> Buy yourself a surface skimmer if you want rid of it.



Or try have more surface movement!


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## Simon Cole (11 May 2022)

Could it be a neuston?      possibly also leaky plants?      I would get a Skim-1, they are a bargain at £8.


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## Hanuman (11 May 2022)

GHNelson said:


> Or try have more surface movement!


I find there is a limit to how much surface movement will take care of biofilm. You can literally blast the surface and still have some biofilm, this is more so true on less well maintained tanks or new setups. Also too much water movement increases evaporation rate, so depending your ambiant temperature it could be quite a lot. In my 90cm tank I usually top up every week ~10L of evaporated water.



Simon Cole said:


> I would get a Skim-1, they are a bargain at £8.


I find the Skim 2 to be excellent. I have tried many brands and even this Chinese brand overtakes Eheim Skim 350 by a large margin.


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## erwin123 (11 May 2022)

For my small desktop tank, a skimmer like the Eheim 350 would take up too large a footprint. I discovered that a usb pump with the intake near the water surface actually acts as a pretty good skimmer. I cut out a 2cmx1cm piece of 100micron filter pad and place it over the intake which I replace every 2 weeks. The 100 micron pad does some filtration and reduces flow and thus the noise/bubbles. The youtube video shows the pump without the 100micron filter pad applied. With the filter pad, there are no bubbles and its silent.

I agree that there will be increased evaporation but since I come from a hot country, the evaporation helps with the tank temperatures (i.e. similar to what you would get pointing a fan at the tank I guess).


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## alnitak (11 May 2022)

Hello, I currenltly use the aquario neo premium acrylic outlet pipe, It has a venturi (adjustable) surface skimmer, that gets rid of the surface biofilm. The great advantage for this skimmer connected to the filter, is that it is situated on the outlet, so if it sucks air, the air doesn't build into the canister filter. It just expells it into the tank (same for floating particles). 
Hope this helps


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## Andy Pierce (11 May 2022)

Surface movement won't sort this problem for you, but an airstone will (certainly did for me anyway:  Aquarium biofilm prevention - Fireplace aquarium).  There's something about breaking bubbles that destroys biofilm.  This means I also predict that you do not in fact already have an airstone - can you confirm/refute that this is the case?


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## ian_m (12 May 2022)

When I got an oily film when I started my planted tank I absorbed it up by floating a piece of kitchen towel on the water when necessary or even better was put an air stone (bubble wall) after CO2 had been turned off.


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## seedoubleyou (12 May 2022)

alnitak said:


> Hello, I currenltly use the aquario neo premium acrylic outlet pipe, It has a venturi (adjustable) surface skimmer, that gets rid of the surface biofilm. The great advantage for this skimmer connected to the filter, is that it is situated on the outlet, so if it sucks air, the air doesn't build into the canister filter. It just expells it into the tank (same for floating particles).
> Hope this helps


The downside being you’re skimming everything into the tank and not the filter.


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## alnitak (12 May 2022)

Yes, into the tank, but no problem at all in fact. The aim is to break the biofilm (as air bubbles do), so it is broken by the skimmer, and disappear very quickly.  For other floating particles, they go back into the tank, and then can be caught by the filter.


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## si walker (12 May 2022)

Andy Pierce said:


> Surface movement won't sort this problem for you, but an airstone will (certainly did for me anyway:  Aquarium biofilm prevention - Fireplace aquarium).  There's something about breaking bubbles that destroys biofilm.  This means I also predict that you do not in fact already have an airstone - can you confirm/refute that this is the case?


Hi.
Correct, I do not have an airstone.
I must say that I like a bit of the old school bubbling. Guess it reminds me of a LFS visit!
I have a usb air pump and will set it on timer to see if it's going to make any difference.
Thank you for that idea!


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## si walker (12 May 2022)

alnitak said:


> Hello, I currenltly use the aquario neo premium acrylic outlet pipe, It has a venturi (adjustable) surface skimmer, that gets rid of the surface biofilm. The great advantage for this skimmer connected to the filter, is that it is situated on the outlet, so if it sucks air, the air doesn't build into the canister filter. It just expells it into the tank (same for floating particles).
> Hope this helps


This also looks like a great option.
Although my space for pipe work etc is really tricky ( it's a long story).
So apparently you can just get the skimmer attachment instead of the whole inlet outlet set? I could try to rig this up to the existing Oase 100 outlet?
It does seem that the Aquario products are pretty rare in the UK. 

In the back of my mind I am also thinking this isn't rocket science, I may try to make something? (who am i kidding?)

Thank you though!


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## alnitak (12 May 2022)

Hello, you can adapt it to oase filter, in fact i bought the full set, inlet and outlet. Acrylic, very easy to set up, to adjust, and to clean. 
This is mine in the previous tank. It is now installed on the large tank, good job, just have to chase floating plants that are fond of canyonning and which accumulate around and inside the skimmer... 😊


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## si walker (14 May 2022)

Airstone worked a treat.!
I am loving the bubbling and get the feeling that the fish are happier!
The airstone stays!
Thank you to everyone that helped on this one!

Simon


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## NatalieHurrell (15 May 2022)

I also use the All Pond Solutions Skim-2.  Currently (due to floating plants) I just pop it in the tank once a week for an hour or so.  Does the trick nicely on my 90cm tank.  £13.00 online.  Bargain.


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## Aqua sobriquet (17 May 2022)

I haven’t found a skimmer that actually works long term without sucking in Shrimps. I was a little dubious but I added a home made diffuser yesterday and it does seem to have got rid of the surface film. I need to quieten the air pump now, or at least put it on a timer so it’s only on overnight.


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## jaypeecee (17 May 2022)

Hanuman said:


> I find the Skim 2 to be excellent.


Hi @Hanuman & Everyone,

Yes, I agree. One of the advantages of a surface skimmer is that it ensures continuous gas exchange - thus ensuring good oxygenation whilst keeping CO2 loss at a low level.

JPC


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## jaypeecee (17 May 2022)

si walker said:


> Airstone worked a treat.!


Hi @si walker 

I don't have a problem seeing why a skimmer removes the surface film because oil droplets, etc. get trapped on a sponge filter. But what happens to the surface film when using an airstone? Am I overlooking the obvious? I'm just curious.

JPC


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## Andy Pierce (17 May 2022)

jaypeecee said:


> I don't have a problem seeing why a skimmer removes the surface film because oil droplets, etc. get trapped on a sponge filter. But what happens to the surface film when using an airstone? Am I overlooking the obvious? I'm just curious.


I don't think why the airstone works is known, but the effectiveness doesn't seem in dispute.  One theory I've read is that when the bubbles break they fling the biofilm in every which direction, some of which winds up getting flung outside of the tank.  I suspect that by keeping the surface film mechanically disrupted the biofilm material either settles out onto the surface or is trapped in the filter (if you have one).  in my non-filtered shrimp-only tank the airstone keeps the surface clear and I do seem to notice some amount of "flingage" around the bubbles but couldn't say whether that's how a meaningful amount of surface film is disposed of.  

To the point about skimmers and shrimp safety, I have seen shrimp get swirled around in the airstone bubbles without apparent ill effect.  I wouldn't say they enjoy it since they don't seem to actively seek out free bubble rides.  This is different from the way the shrimp do seem to seek out sitting in a water flow over a surface:  River run - Fireplace aquarium (see the 'shrimp on a shelf' video).  Weird but they do this all the time.  I think there is some kind of "swim upstream" instinct in these guys.


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## jaypeecee (17 May 2022)

Andy Pierce said:


> I don't think why the airstone works is known, but the effectiveness doesn't seem in dispute. One theory I've read is that when the bubbles break they fling the biofilm in every which direction, some of which winds up getting flung outside of the tank.


Hi @Andy Pierce 

Many thanks for your reply. I was beginning to think on similar lines to what you have said above. But I wasn't sure if my imagination was just having a field day!

JPC


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## NatalieHurrell (22 May 2022)

Andy Pierce said:


> To the point about skimmers and shrimp safety, I have seen shrimp get swirled around in the airstone bubbles without apparent ill effect. I wouldn't say they enjoy it since they don't seem to actively seek out free bubble rides. This is different from the way the shrimp do seem to seek out sitting in a water flow over a surface: River run - Fireplace aquarium (see the 'shrimp on a shelf' video). Weird but they do this all the time. I think there is some kind of "swim upstream" instinct in these guys.


I've observed it too.  Ours are the first in the queue at waterchanges for bubble rides and have a mad half hour every night, doing laps of the entire tank going against the flow!


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## fredi (29 May 2022)

Andy Pierce said:


> I don't think why the airstone works is known, but the effectiveness doesn't seem in dispute.  One theory I've read is that when the bubbles break they fling the biofilm in every which direction, some of which winds up getting flung outside of the tank.  I suspect that by keeping the surface film mechanically disrupted the biofilm material either settles out onto the surface or is trapped in the filter (if you have one).  in my non-filtered shrimp-only tank the airstone keeps the surface clear and I do seem to notice some amount of "flingage" around the bubbles but couldn't say whether that's how a meaningful amount of surface film is disposed of.
> 
> To the point about skimmers and shrimp safety, I have seen shrimp get swirled around in the airstone bubbles without apparent ill effect.  I wouldn't say they enjoy it since they don't seem to actively seek out free bubble rides.  This is different from the way the shrimp do seem to seek out sitting in a water flow over a surface:  River run - Fireplace aquarium (see the 'shrimp on a shelf' video).  Weird but they do this all the time.  I think there is some kind of "swim upstream" instinct in these guys.


Is it possible the the bubbles break the surface tension


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## Andy Pierce (26 Jun 2022)

Updating on the airstone, when mounted on the upper side of this open-topped tank the stone did fling out a significant amount of water and debris, so much so that it was becoming problematic.  I moved the airstone to the middle bottom of the tank and that has fixed the flung-debris issue and the biofilm has not come back either (video link:  Airstones can be messy - Fireplace aquarium).  I'll keep track going forward but it looks like an airstone prevents biofilm formation by mechanical surface disruption.  I don't know where the biofilm-disrupted material goes... hopefully into the water column and onto submerged surfaces so it can be eaten by the shrimp!


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