# film on top of tank



## violentray (Jul 20, 2005)

i ahve a 30 gallon planted tank i just set up about a week ago. i am running a DIY co2 set up and i have a film on the top of the water. i also have a 20 tall that i am not injecting co2 in and i do not have this film.

i am using a difuser that i cant remmeber the name of, but it has a spiral on the inside and a disk on the top that emits super fine bubbles. i have the bubbles going up into the outflow of my H.O.T. magnum canister filter and being blown around the tank.

the Co2 goes out the 2 liter bottle and into a small gatorade bottle half full of water and from there into the difuser. i thought that gas seperator would prevent gunk in the tank. 

anyone have any answers how i can fix this film problem. i can post pics of the Co2 setup and difuser later if needed.


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## apistaeasy (Jul 16, 2004)

Champagne yeast is finer in texture than baker's yeast, and prevent the "gunk"
It's really hard to say what your film is though...


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## werner (Jul 6, 2006)

Might just be plain ol' surface scum. Do a search for "surface scum" or "surface film" for tips on removing it.


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## violentray (Jul 20, 2005)

while it could be surface film or scum. i think it is odd that it is only on one of my 7 tanks i am running. also it is the only tank with CO2.


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## bigstick120 (Mar 8, 2005)

It may also be bacteria as it is a new tank.


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## snowhillbilly (Mar 29, 2006)

Just out of curiosity are you using some kind of soil substrate?


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## werner (Jul 6, 2006)

> while it could be surface film or scum. i think it is odd that it is only on one of my 7 tanks i am running. also it is the only tank with CO2.


My guess: in order to keep the CO2 from escaping, you have reduced the surface agitation on this particular tank. Less surface agitation means the scum isn't breaking up. Surface scum: The Skeptical Aquarist


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## violentray (Jul 20, 2005)

my substrate is florite and natural looking gravel, not the clown puke colored stuff. the florite was taken out of a different tank.


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## snowhillbilly (Mar 29, 2006)

I have the same surface scum that you are talking about, but I have a soil bottom tank. So much for that theroy. If you take a paper towel and set it on top of the water does this take the scum out? It works for me.


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## violentray (Jul 20, 2005)

yes it does come off somewhat easily with a paper towel.

i just think it is some sort of scum coming from the DIY Co2 mixture. i was wondering how to prevent this from occuing with out going to a pressurized system. the way my tanks are laid out I cant have a pressurized system, i just dont have the room.


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## stepheus (Jun 13, 2006)

I have tried DIY CO2 for a while and IMHO I don’t think it is due to the DIY CO2. That unless you have noticed that the liquid from the DIY bottle, flowing into the aquarium thru the tube. 

Since you did mention that your tank has only been set up for a little more than 1 week, the layer of scum might be due to excessive ammonia build up in the tank...as the bacteria colony to break up the ammonia is not matured enough to cut it down. Give it a while, let the tank mature and see what happens.

While you wait, do not add fauna to your tank, as they will contribute to the production of ammonia. And since you have older tanks, you can speed up the maturity of this tank by washing your filters into this tank (yes...washing the fish excrement into the new tank). It might sound boogey at first, but it is called "cycling". Along with the fish excrement, beneficial bacteria will be washed into the tank as well. Try google "fishless tank cycling". Although your tank does not have inhabitants, the ammonia might be due to non-beneficial bacteria feeding on the rich fluorite soil or other nutrients in the tank, thus creating the film.


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## violentray (Jul 20, 2005)

the tank is currently stocked with 11 angelfish, 6 Panda Cories, 4 Apistogramma Caucatoides, and 6 Oto. i plan on doing a large water change tomorrow and i will add som old tank water from a different tank to this newer tank.


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## @[email protected] (Jul 10, 2006)

That's quite a large bioload for a newly setup tank. Angels eat a lot and excrete a lot. Try feeding less. Sometimes it may just be excess feeding that's causing built up in surface film.


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## Raul-7 (Feb 4, 2004)

I've heard many theories about what surface scum really is, but I can narrow it down to either insoluble lipids and protein, or heterotrophic bacteria.The bacteria colonies feed on excess nutrients, and if I remember they can only be seen when the lights are on. After dark, the colonies usually disperse. As for the lipids, they form an oily thick residue and remain bound together untill they are broken up at the surface.

Your best method is to use something that actually 'breaks' the surface of the water, ie. an airstone after the lights go out or even better a surface skimmer.


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## nap83 (Feb 7, 2006)

i had this problem in my 10g tank since it had no filter and water was basically stangnant because i didn't want any co2 loss. i'm pretty sure it's because of the diy co2 but of course i could be wrong. i wanted to eleiminate the problem with a "flow" of water on top of the tank but it would defeat the purpose of getting co2 to dilute in the water efficiently. 

then i stumbled upon an article that hoa g. nguyen wrote on his yahoo website stating that black mollies effectively eat green algae along with surface scum, so i tried the little bugger... and yes it works, they literally drink it out of the surface. 

something to consider. good luck.


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