dirty water surface....

[twoodrough]

Ammonia 0, Nitrite 0, Nitrate under 20, 20 gal community (1 female betta, 3 cherrys, 4 serpaes, 1 zebra= 9 total fish), temp 81, last PWC 25% yesterday, last PWC before than 25% 4 days before, and 2 PWC the week before as well, last filter cartridge/carbon change 3-4 weeks ago, tank is 5 months old

The surface of my water has a coat of dust/slime/oil/something. It goes away for a few hours after a water change, but does come back. I had this with a previous tank as well. Is it normal? If not, how to fix it? What to check?

Thanks!

 

[mfdrookie516]

It's called bio-film. Adding surface agitation will cure this.

 

[eco23]

If I remember correctly, this is a protein film. Its usually caused by not enough surface agitation. Adding an airstone, a powerhead or lowering the water level so the filter splashes onto the surface should fix you right up

*whoops, rookie beat me to it, lol.

 

[twoodrough]

I had an airstone but liked the quiet when I took it out. The tank is in the living room with the TV. I will take out a gallon or two and see what happens. Thanks!

 

[eco23]

I had an airstone but liked the quiet when I took it out. The tank is in the living room with the TV. I will take out a gallon or two and see what happens. Thanks!

Same happened to me. I switched to a canister filter which was almost silent, and I turned off my airstones to enjoy the quiet. I started getting the same film after a few days of turning it off. It cleared up pretty instantly once I turned the air pump back on.

 

[adadkins1]

I had this problem before I put a filter on my betta's tank. What kind of filter do you have?

 

[twoodrough]

I have a Tetra 20-40. I would have thought with having a larger filter the water disruption would be enough to not have a biofilm problem. Apparantly not. Lowered the water a bit and that took care of about 80% of it. Now to decide if I lower the water to where I am going to see the water line, or put the air pump and stone back in and live with the noise. Hmmmm.....