# Surface Scum



## Emily6 (Feb 14, 2006)

Ok, here's another problem I can't seem to fix- what's with the surface scum? Periodically I get this nasty gray thick scum on the water surface. I've heard lots of thoughts on this- not enough water movement, too much protein, bacteria... but it comes and goes every few months with no changes made by me. I notice it more often when a fish has died- protein? But why doesn't it go away and how is there enough floating protein from one dead fish to cover an 18" x 36" area with a thick goo?!?

Anyway, again- all theories appreciated.


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## Emily6 (Feb 14, 2006)

Just cleaned the tank- filter intake was very clogged and it seemed possible the filter never re-primed after last cleaning... maybe there really wasn't enough surface movement this time.


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## lanceduffy (Jul 15, 2010)

I would love to hear a concise and exhaustive explanation of this phenomenon. 

I too have heard different explanations of why this occurs. 

It would be awesome if people could post links to explanations and experiences here. 

From a practical point of view, I have been using the scum as an indication that my filter needs servicing. If I aerate every night via lily pipe, I don' get scum. If I aerate every night via lily pipe and still get scum, I clean my canister and in a day or two after cleaning, I am back to no scum as long as I aerate at night.


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## doubleott05 (Jul 20, 2005)

its a protien film. 
I get it all the time. 
dosent hurt anything. 


if your really worried about it fluval makes a canister attachment that i used to use back in 2005-2006
its a surface skimmer attachment

Thanks


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## lanceduffy (Jul 15, 2010)

Protein film from what?


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## Gordonrichards (Apr 28, 2009)

Its caused by stagnant water and gravity/surface tension. Bacteria biofilm, natural process. 

Increase the flow, and away it goes!


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## lanceduffy (Jul 15, 2010)

Ok, so here is where I am confused. I have heard this called a protein film and a bacteria biofilm. 

Are these one and the same? To me it don't seem so. I mean we don't interchangeably say we have protein or bacteria in our filters. 

Could someone please enlighten me?


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## niko (Jan 28, 2004)

The film is actually a carbohydrate structure in which the bacterial live. I guess there are proteins beeing made or discarded. It's a complicated structure actually - more like an entire civilization with layers and channels and what not. It's an amazing thing except we find it ugly and it also blocks light and hinders gas exchange.

Yes, it is an indication that something is not right with the biofilter. ADA takes care of this film by raising the filter outflow so the surface of the water is stirred and incorporated in the water body which eventually leads to the pieces of the film being sucked by the filter intake. Also ADA uses the Lily pipe to create a gentle vortex that also sucks the film and incorporates it in the water body. In Western countries we use ugly plastic "surface skimmers" with the same effect. Either way - the goal is to incorporate the biofilm in the water so it becomes invisible and eventually gets sucked by the filter.

--Nikolay


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## James0816 (Oct 9, 2008)

Bacteria film, Protein film ... all in all ... it is just plainly called Biofilm. It is a very normal occurance in any tank.

Sry Niko, but I will have to disagree that it is an indication that something is not right with the biofilter. 

I have no links, studies or research to provide so take it with a grain of a salt.

The only thing that it really signifies is that there is not alot of surface aggitation to keep things moving in the tank.

I pay it no never mind. Just run an airstone for a few minutes to stir things up and you'll be good to go again. 

To prevent it, increase the surface aggitation via the filter flow, power head or air stone.


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## Gordonrichards (Apr 28, 2009)

A+ responses to everyone!


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## Emily6 (Feb 14, 2006)

Thanks for all the great responses! I more or less figured out that increased surface flow fixed the problem and I hafve recently noticed that my filter intake has been very clogged- resulting, I'm sure, to an overall descrease in flow. Guess all my suspicions are confirmed!


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## jeff5614 (Feb 15, 2006)

James0816 said:


> Bacteria film, Protein film ... all in all ... it is just plainly called Biofilm. It is a very normal occurance in any tank.
> 
> Sry Niko, but I will have to disagree that it is an indication that something is not right with the biofilter.
> 
> ...


I'm going to agree with Niko based on what I've read in Aquajournal. Anyone who wants can read it by going to the link I've given. I will say that biofilm has become a thing of the past in my tank. I added a set of lily pipes, provide good aeration at night and other than a coarse pad and very thin layer of floss in my Eheim I'm only using biomedia along with adding Green Bacter after each water change. Tell me none of this matters if you want and that Green Bacter is snake oil but I have crystal clear water and no film on the surface. With previous filter set ups which concentrated more on mechanical and chemical filtration and used spraybars to output the water, I had to install a surface skimmer to eliminate the build up of surface film.

Here's the Aquajournal link. http://www.aquajournal.net/na/rescue/filter.html


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## lanceduffy (Jul 15, 2010)

> jeff5614 said:
> I'm going to agree with Niko based on what I've read in Aquajournal. Anyone who wants can read it by going to the link I've given. I will say that biofilm has become a thing of the past in my tank. I added a set of lily pipes, provide good aeration at night and other than a coarse pad and very thin layer of floss in my Eheim I'm only using biomedia along with adding Green Bacter after each water change. Tell me none of this matters if you want and that Green Bacter is snake oil but I have crystal clear water and no film on the surface. With previous filter set ups which concentrated more on mechanical and chemical filtration and used spraybars to output the water, I had to install a surface skimmer to eliminate the build up of surface film.


This is what I was talking about when I said this:



> From a practical point of view, I have been using the scum as an indication that my filter needs servicing. If I aerate every night via lily pipe, I don' get scum. If I aerate every night via lily pipe and still get scum, I clean my canister and in a day or two after cleaning, I am back to no scum as long as I aerate at night.


Works for me too.


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## Emily6 (Feb 14, 2006)

So the scum keeps regathering after water changes and stirring and filter adjustments- I took everyone's thoughts into consideration and attacked my filter- first, I took off the pantyhose cover on the intake (prevent shrimp baby deaths)- it was clogged. This didn't fix it.

Then I took the filter apart and scrubbed all the hard surfaces clean- the impeller was pretty gnarly so I was hopeful this would be the fix. I replaced the media, gently rinsed in tank water. Again, nothing.

Then I forgot about it for a week while I anxed over my pH/CO2 problem- I was dosing Excel to compensate for the CO2 the water couldn't buffer and in the process killing off shrimp (gah!)- this issue sucked up all my mental powers (and isn't over yet).

I sat back and thought about it and the whole while this scum has been about, shrimp have been dieing en mass. The last time I had the scum problem, an old fish was decomposing somewhere out of site and once I removed it, the scum went away. Is the scum limiting gas exchange and killing things or...

Is it possible the dead fish/shrimp protein is feeding said bacteria and those of you who have this scum routinely just feed your fish more protein-rich foods? 

My tank is properly cycled and all the basic tests show that ammonia is breaking down- what could be wrong with the bio-filtration?

Sorry for the almanac. :-/


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## lanceduffy (Jul 15, 2010)

Thanks to everyone for the input on the bio-protien-carbo matrix.

Ok then, back to basics. Give us your relevant tank parameters: size, light type, light duration, filter type, input / discharge pipes, filter media, co2 type, co2 period, co2 diffusion method, ferts, method of dealing with dead things - plant, fish, shrimp, and feeding method. Oh and substrate.

My first suspicion is tat you are letting organic compounds build up in your tank and the bio filter can't handle them. Your comments about the dead fish/shrimp and the clogged filter intake sock lead me to believe you may not be getting rid of this stuff quickly enough and the bio filter is having to work double or triple time to break down this stuff for you. Removing this stuff quickly can ease the burden on your filter.

I also think your bio filter may have been weakened by your recent maintenance. Please search around these forums for information on filtration. Niko has a great thread called "a very excited word about filtration" and his Dummy Question series are pretty good too. 
Read this: http://www.aquajournal.net/na/rescue/filter.html
and everything else on the pages on that site.

Oh and have fun!


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## Emily6 (Feb 14, 2006)

Ok-

I have a 65 gal w/ 4 x 39w T5ho lighting for 10 hours a day. I have a CO2 difuser plumbed into the filter outflow, which is about mid-level. The tank is 24" tall. The CO2 is connected to a pH controller, set to 6.5. Right now I think I have a buffering problem so the CO2 tanks the pH immediately and therefore isn't on very long.

I use EI dosing accordingly with the size of the tank. 

I would agree with you about the maintenance being bad but the problem existed before I touched the filter. The sock was there for a month without being cleaned and it seemed the shrimp would graze on the stuff it caught, helping to prevent more build-up. I removed it a few weeks ago, then attacked the filter itself. No change in between.

I only have a few small fish, 2 3" loaches and shrimp so I don't feed a whole lot. I do weekly 50% water changes, carefully trying to get everything off the substrate that I see. 

The dead shrimp are often scarfed up by my two clown loaches before they decompose, so I don't really think they're contributing a whole lot to the bioload problem. I'm sure they miss a few though. 

Thanks for the link- I read it through and didn't find anything contradictory to what I'm doing (phewf!).

Right now, I think it's possible my filter is recovering from all the nasty stuff I dumped in/on the tank to treat for clado (H2O2, mostly), then the Excel OD's, and now what seems to be some substrate buffer exhaustion. I'm going to just give it time and work on the buffer problem first.


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## lanceduffy (Jul 15, 2010)

Ok, sounds like you have invested some money into this setup. I hope something that I write below can help.



Emily6 said:


> Ok-
> 
> I have a 65 gal w/ 4 x 39w T5ho lighting for 10 hours a day. I have a CO2 difuser plumbed into the filter outflow, which is about mid-level. The tank is 24" tall. The CO2 is connected to a pH controller, set to 6.5. Right now I think I have a buffering problem so the CO2 tanks the pH immediately and therefore isn't on very long.


Take care to be sure that your buffering problem is not a faulty PH probe. I personally do not use one of these systems. I have heard lots of stories about these systems causing problems because the probe has a problem and gives a false reading. The result is fish death due to too much gas or lots of algae due to too little gas.

What are your water parameters out of the tap. You are using tap water aren't you? 



> I use EI dosing accordingly with the size of the tank.


If you are dosing EI with that much light and not adding much CO2 you are sitting on an algae time bomb. You know this though.



> I only have a few small fish, 2 3" loaches and shrimp so I don't feed a whole lot. I do weekly 50% water changes, carefully trying to get everything off the substrate that I see.
> 
> The dead shrimp are often scarfed up by my two clown loaches before they decompose, so I don't really think they're contributing a whole lot to the bioload problem. I'm sure they miss a few though.


Depending on how many dead shrimp we are talking about the end result of this could be the same as overfeeding: lots of fish poop.


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## lanceduffy (Jul 15, 2010)

Oh sorry, I just read your other thread about your water turning acidic. That answered some of the things I was curious about. I really can't help any more. Your water parameter issues are above my level of understanding. Good luck.


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## Emily6 (Feb 14, 2006)

That's ok- I made two threads not realizing the two problems might be related.

Anyway, I routinely check my pH probe, double so when there's a CO2 question at hand. I work with them routinely as my job so I know what you mean- they're very sensitive and easily damaged.

The algae at the moment isn't catestrophic. Merely the staghorn, which goes away easily, and some black brush that's always been a small nusiance. 

Thanks for your help! I'm going to work on the water hardness (or lack thereof) problem first and see what that does.


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## APlantedAquarium (Jul 1, 2011)

Yep, I used to get this until I got a surface skimmer that got it to go away.


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## wwh2694 (Aug 15, 2008)

I used to have those ph controler for my co2, i just want to tell you that you dont need those. Those things will lessen your co2 when your buffer goes down. Its much better if you run your co2 on a timer and a co2 indicator. I think this will solve ur problem. You need to have a consistent co2 tru out.


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## Emily6 (Feb 14, 2006)

I added Equalibrium and so far the CO2 has been running much more frequently. I added a little Excel to help kill some of the algae that cropped up. 

Right now the pH controller makes sense for me- I can only work on my aquarium during the weekend- I work out of state. So should something go wrong, it at least limits the catastrophe. I do check it's calibration often though.


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## Emily6 (Feb 14, 2006)

Not sure if anyone's hanging in there with me on this but in case you are- 2 days after adding Equilibrium, the algae boomed in the tank and the scum was apparently so thick it was nearly solid. Sooooo... I went back to the books.

Tom Barr had a cool article in 2003 about a theory that stressed plants leak lipids. The varieties of algae I have (black brush and staghorn) thrive in CO2 shortages. My ground cover plant is now a lawn of death and everything else looks miserable. 

My thinking is that when I increased the ferts a few weeks ago, maybe the limiting factor became CO2, allowing the algae to run rampant. I'm still confused why adding the Equilibrium would have made everything worse so quickly. The scum was stirred thoroughly, though, and has diminished since Sunday. But still...

Anyway, I'm lowering the pH meter to 6.0 now so the CO2 will stay on longer. All my fish can handle that so let's see what this does. ](*,) I see the merit now in life without a pH meter. Conversely, w/o being there during the week, I feel safer with one.


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## lanceduffy (Jul 15, 2010)

Its been a while. Hope all is well. I am mainly adding this for posterity (incase someone does a search and wants information.) 

Somebody out there has exact numbers and may chime in. If your PH is too low, the bacteria you need in your tank and filter cannot live.


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## Virc003 (Aug 18, 2011)

Snails will eat it. I set up a 10gal without a filter, and the first month or so the scum was getting quite nasty until one day I saw a snail, upside down, siphoning the surface of the water. It was gone in a few days.


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## mudboots (Jun 24, 2009)

I have just set my 36 now front back up after the kids finally got tired of rainbow gravel and laughed when I got my surface skum back. I have the tank only 3/4 full and had to rig up some pipe for intake and output...and don't want much agitation because I will eventually put a very sensitive aquatic frog species in that setup. I had to re-research what exactly the layer meant. Personally I am glad to have it because the lights would otherwise be too intense.


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## mudboots (Jun 24, 2009)

Bow front...not "now" front...silly auto-correct


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## mudboots (Jun 24, 2009)

Bow front...not "now" front...silly auto-correct


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## Michael (Jul 20, 2010)

Mudboots, nice to hear from you!


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