What is this mystery surface film?

[mhallstr4]

Hi Reefers,

I have a mystery I’d like to ask our community? What is this mystery film on the surface of my 25 gal Watebox? It’s grey white and oil-based see picture. When I add a flake of food, the film rushes away to reveal clear water. It appeared about 10 days ago- about the same time my filter sock began to look like the second picture.

The tank has been up since Sept 21. Added one small clown fish Nov 21. No other livestock.

Water parameters as of an hour ago:
-ammonia: 0
- nitrite: 0
- nitrate 2 ppm
- salinity: 32
- temp: 77.6 F

I removed the filthy filter sock, skimmed some of the oily junk, and started up the tank

Because the tank is new, I keep the light off all the time. The tank has 10lb of live sand, 2lb live rock, and 18-20lb of dry rock. In 3 locations, rock is bonded together with instant ocean holdfast epoxy. I feed a few flakes of food to the fish every day. Fish appears happy and healthy.

what is the film? Is it a problem? How do I fix it?

 

[Bao]

Is the water level in the filtration compartment the same level as the tank? Any film on the tank surface should had flowed into the filter sock.
by the way, I don’t see any pictures

 

[mhallstr4]

Water level in filter compartment / back sump is higher thank the tank. Attached here are pics.

Also, is it common for filter socks to get this dirty from one fish in one month? How do I clean these things? Or donI boy more?

 

[Bao]

The water in filter compartment has to be lower than the water in the tank. That’s why that film stayed in the tank and didn’t flowed into the filter sock. Yes, one me fish can produce a lot of waste and also depend on the amount and the kind of foods that you feed. For filter sock to be effective, you have to clean it more often than once a month.
generally you would need to change water, carbon, Gfo and maybe a skimmer to help with filtration

 

[mhallstr4]

Thanks Bao. If a new filter sock makes the film disappear, then you are right. I have a couple on order.

I’ve had tanks before and not seen this film. What is it?

 

[DJTank]

Yeah, looks like detritus film from excess feeding or maybe from organics on new rock. Skim on regular water changes and follow what Bao said and you should be good if that is the problem. You want to be sure you keep it clean as it will limit oxygen exchange.

 

[Joe Rice]

Also, is it common for filter socks to get this dirty from one fish in one month? How do I clean these things? Or donI boy more?

If you're using a filter sock as a method of reducing (exporting) nutrients you need to replace it before the particulate matter it catches begins to break down. I replace mine every 3 days.

I have 10 socks and when I get to my last one, I throw the dirty ones in the washing machine with a bit of detergent and a decent amount of bleach, run a normal cycle with the extra rinse option, then run two more quick cycles also with the extra rinse option. Then I take them out and let them air dry for at least two days.

 

[coralfishreef]

For a 25 gal, disposable filter floss is more convenient for me. A big bag of Sera filter wool is less than $20 and lasts a long time.