white film.

timwag2001

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Apr 25, 2009
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what is the cause of a white film that is on the surface of my water? it builds up quite frequently. i stick a cup in the water and skim it off. i'm gonna try to get a pic when i can find my camera.

any ideas?
 
You need more surface agitation.
 
It's composed of food particles that are insoluble in water, such as fats, oils, proteins, etc. and some of the bacteria and fungi that feed on them. There's no real "cure" for it other than don't feed your fish, but high flow rates and surface agitation will distribute it back into the water column.

I've heard of mollies eating it before, but I've not witnessed it first-hand.
 
I'm just starting to develop this now myself. I skim it off or re-direct my filter. It sucks to get rid of, because by increasing surface agitation I am off-gassing more CO2
 
thats what i was thinking about increasing surface agitaion. i dont want to offgas co2.

could the brand of foood i'm using be causing this more than another brand?
 
It's mostly composed of aerobic bacteria that are eating the oils and other organic molecules from the food. Surface agitation works because it mixes the bacteria and food throughout the tank. Changing foods might help but it doesn't always solve the problem. All foods have some fat.

A powerhead may help by circulating the water in the tank more without outgassing CO2 too much.

I've only personally seen this happen on a 2 gallon bowl that I had some ghost shrimp in. I didn't have a filter or an aerator on the tank, just a light and some plants. I finally dismantled it after a few months because I was sick of the film formation. The plants were very happy and did just fine.
 
ok. increased water flow at the surface. the film looks much better but now my water is getting cloudy. in a white cup the water doesnt look green. it looks a little tiny bit brownish if anything. whats going on?
 
What you can try is hook up a PH to a timer. Aim PH at surface, and set time for night (when you need more O2 anyway).

This way during day CO2 stays in tank, at night surface is agitated and more O2 is avail for fish.
 
What you can try is hook up a PH to a timer. Aim PH at surface, and set time for night (when you need more O2 anyway).

This way during day CO2 stays in tank, at night surface is agitated and more O2 is avail for fish.

Do you think that an airstone on a timer would also accomplish this? I also have some of this film, but am not too annoyed with it. I'm also concerned with the off-gassing of the co2, although i'm using DIY and not pressurized.
 
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