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.