Persistent biofilm

[20gallonreefer000]

I have had this oil-like, brown & green biofilm that doesn't seem to go away. I've tried manual removal, carbon, surface agitation, etc. My parameters are good and have been consistent for the past 3 years. My corals and fish are not affected thankfully, but the film makes simple tank maintenance a pain. Thanks in advance.

 

[OnlyZoas]

Commenting so I can see what others suggest. I don’t get a film as opaque as yours but my tank does get this type of build up. I don’t have a skimmer while it looks like you do so that’s interesting.

I usually manually surface skim with a cup when I notice it. And just today I tried the cling wrap trick and it definitely made a difference.

 

[20gallonreefer000]

Manual removal helps temporarily in my case, but it pops back up quick :(

 

[ogtumblruser]

food? every time I feed reefroids, benepets, or mysis it tends to add a film. But when i can't get rid of it I bring a powerhead up to the surface until it bubbles and leave that running for a couple minutes, display will act like a skimmer and then siphon bubbles that collects in the corners with syringe and discard or into the skimmer.

 

[Brickz]

Commenting so I can see what others suggest. I don’t get a film as opaque as yours but my tank does get this type of build up. I don’t have a skimmer while it looks like you do so that’s interesting.

I usually manually surface skim with a cup when I notice it. And just today I tried the cling wrap trick and it definitely made a difference.

 

[Clarkjw2002]

You need something with a surface skimmer. They make HOB filters and canister filters with them. Something like a Sachem Tidal HOB or Tunze comline skimmer. Otherwise, you'll never permanently get rid of the slick. In your pics it looks like you have film algae/cyano growing on it too.

 

[Mr. Mojo Rising]

If your picture is your surface agitation, to me thats not much agitation. The surface of my tanks looks like white water rapids, that may be overkill but you should at least have some strong ripples going across the surface, I like to see the occasional tiny bubble enter the water from the amount of agitation.

You need more surface agitation to mix that stuff back into the water so that your filtration can filter it out. Move your powerheads to just a few inches below the water and aim them up.

The surface film cuts the light and also cuts the gas exchange (cutting the oxygen level), as well as it is unattractive, so its important to get it resolved.