Strange problem with film on the top of the water, opinions anyone?

[bikeguy1]

For the last few weeks I've had an oil slick like film on the surface of my DT and in the return chamber of my sump. My sump has 3 chambers in this configuration: drain/skimmer>return<-refugium. I have overflow water from the DT draining into both the skimmer area and the fuge. I also have some of the water from the return area flowing through the fuge.

A few days ago I cleaned the sump and completely drained, cleaned and dried the return area. I also used paper towels to remove what I could from the DT water. After the water change everything seemed great. I don't have anything on the surface of the DT now but I am seeing the film in the return area of the sump again, but nowhere else. In the return chamber I have 3 heaters and a MAG18 pump. The Mag has nothing in it that could bleed into the water that I know of.

Would something in the heaters be causing this? I'm thinking about replacing them and see what happens but it has me pretty stumped. I was also thinking it could be the skimmer pump and the water in the skimmer area has enough flow that the film can't form but that doesn't seem like it's the case. The tank has been running for about 2 years with no issues.

Any help/ideas/opinions would be appreciated. Hopefully I've provided enough info and its not too confusing.

Thanks

[benzreef]

The return section doesn't have much agitation at the surface usually, and you may notice a build up. Same thing for the DT if there isn't much agitation at the surface. Maybe try to point your powerheads toward the surface of the DT. Same thing for the return section if you have an extra PH or two.

[Palting]

The biological processes produce organic substances, some of which are oily and float on top of water. That's normal, but can be unsightly in the DT. Surface skimming, surface agitation to get the film back in the water column to be processed, there are effective means of getting rid of them

[bikeguy1]

Thanks for the replies. I thought that agitation may have been an issue but I haven't changed anything for quite some time with no problem. I have 2 Koralia's in the DT plus I have the return nozzles tilted up a bit creating quite a bit of agitation. I don't have much agitation in the return area of the sump but I also don't have much in the fuge either with no film. The fuge gets water from the DT and the return so it would make sense to me that I would see some in there as well. Maybe I will try a powerhead in the return and see what happens.

[philosophile]

What kind of overflow do you have?

[Addicted2coral1]

You know i have tried several things for this, actually even gave up and let it go a bit for a while, but let me tell you its worth it to agitate the top of the water, so much more light gets through and also more stuff seems to get skimmed out. The surface on my tank is agitate very well and i have no build up and the pentration of light is great...

[bikeguy1]

What kind of overflow do you have?

The tank is a 95g AGA wave front tank with an internal overflow.

The sump is a 55g acrylic tank that I built myself. The DT is on the first floor of my house and the sump is in the basement.

I'm not having an issue with the DT right now, just the return section of my sump which is why I am puzzled. All 3 sections of my sump have the same water running through them in some capacity but I only see the film in the return section which in theory should be the cleanest water in the tank. That is why I thought the heaters or the pump might be the problem.

[Tim gixxerman]

Do you have a skimmer or run a filter sock?

[bikeguy1]

I am running a Vertex skimmer, no sock.

[Tim gixxerman]

Can you crank it up?

[Indymann99]

The tank is a 95g AGA wave front tank with an internal overflow.

All 3 sections of my sump have the same water running through them in some capacity but I only see the film in the return section which in theory should be the cleanest water in the tank. That is why I thought the heaters or the pump might be the problem.

having surface scum in the return section is common. If you observe your other sections water is flowing across the TOP of the water over the baffle and into the return section. In the return section there is nowhere for the surface water to "flow" (the return pump just sucks it down from the bottom) so a scum forms on the surface. Some put in a small power head to agitate the return section... my return section is small compaired with the rest of the tank + sump surface area so I dont consider it a problem.

vid of DT surface ag
http://i300.photobucket.com/albums/nn10/Indymann99/th_Surfaceag.jpg (http://s300.photobucket.com/albums/nn10/Indymann99/?action=view&current=Surfaceag.mp4)

[Jake007]

Agree with other posters. I had a similar problem in the DT. I redirected the power heads to better agitate the surface water and also added a filter sock and the problems went away. Also consider, crank up the skimmer to skim wetter for awhile.