Surface Film

[AaronReef]

All of a sudden, in the last 48 hours, my tanks have developed an oily film on the surface. I'm beating the heck out of the surface with current, but in the few areas where it's not rippling, the film remains visible, and if I shut off the pumps, the film covers the whole surface.

The skimmers have also slowed down in the last week or so, with very little skimmate being produced.

The only parameter I'd describe as "marginal" is the PH, which has been running close to 8.0 in both tanks, which I'm pretty sure has to do with CO2 buildup inside the house. SG 1.026, dKH 11.4, Calcium 430, Mag 1400+, temp 79-81, Nitrate 15 in one tank, 40 in the other.

These are two seperate systems, both exhibiting the same behavior. It seems as though there has been a change in surface tension that is preventing the very surface of the water from heading down the overflow.

I've heard there is a relationship between PH, surface tension, and skimmer performance. Anyone have any ideas?

 

[Gary Majchrzak]

when I notice issues with surface tension/skimmer performance it usually coincides with something in the air- greasy foods being cooked (Italian sausage) or candles being burned.

Oil slicks most often occur in aquariums not having a surface skimming prefilter but I know you have them on your aquarium, Aaron.

 

[BWIPlumbing]

i have read somewhere about laying a newspaper on the water surface to get the oils to attach to it and then remove it.. never tried it.

 

[5380]

I usually clean my skimmer's air intake at this point and then do a water change with airline hose skimming the surface. If possible add mechanical filtration on an overflow.

 

[tmz]

It's not ph.
Some oily(hydrophobic) substance from the air, food,an oily sustance put in the tank or ungloved hands in the water could lead to the film and bubble popping which would lead to a drop in skimmer performance.
Ultimately the oil will be broken down by bacterial metabolism, or driven out in small droplets by the skimmer if new sources are not added.
As Gary noted cooking greasy foods might be an issue. Lotions on your hands could be an issue. Supplements like selcon could cause it. Citric cleaners or scentd candles could be problematic. I've seen bubble popping after using too much of the red colored epoxy at one time.
Water molecules are attracted to one another. The hydrophobic oils are squeezed towards the air at the surface as the water molecules bind to each other. Agitation helps oxygenation but just drives the oily organics back below the surface of the water to be squeezed out again.
Surface skimming should move them to the sump for removal by the skimmer where the may cause the bubble popping for a while.Oily molecules get between the bubbles and cause them to join up , become larger and ultimately pop( commonly referred to a surface tension problem).
They are organic so granulated activated carbon may help.

 

[Gravesj1s]

+1 to what tmz posted. Also, just putting your hands in the tank can cause the skimmer foam to colapse. Our hands have a natural oil that cause this.

 

[jfl14609]

I had this happen a few times in my two experiences it was actually just that a pump that I used to agitate the surface needed a little cleaning sounds more like yours is more oil mine was more like protein crud but you never know

 

[diverdick]

A surface skimmer should peal any surface gunk right off the tank. Take a closer look at your surface skimmer function. This happens to me when flow is reduced in the pump/sump loop and the water level in the tank rises slightly (due to gunk & air bubbles in the U tubes). In my case, the system pump loop slowes when pump maint. time nears. I take the main pump down every 6 months to acid clean the wet side (rid the flow robbing calcium build up). In that there is les flow in the pump loop, my U tubes will take in air with the lower velocity of water flow. Once the air pocket develops, the overflow capacity is reduced significantly. Again, in my case, the water level in the dispaly rises a bit, screwing with the water flow into the overflow. In turn causing the surface to become stagnate in certain areas. The longer this situation goes, the more of the surface is affected.

 

[Conesus_Kid]

You're not feeding frozen PE mysis by any chance, are you?

 

[belgian_waffleman]

I have the same issue. Are you saying that increased flow from the sump will help?

Waffleman

 

[scott473]

What do you heat you home with? The past few days have put furnaces and heaters into over drive.

 

[tangstank]

Lower your return tube in your overflow so more surface water flows into the sump through skimmer.

 

[tmz]

I have the same issue. Are you saying that increased flow from the sump will help?

Waffleman

:wavehand: I think inreased surface water to the sump can help once the skimmer mists some of the hydrophobic oil out and bubble popping stops( water tension issue) .

 

[AaronReef]

Thanks for the help everyone.

The event seems to coincide with the weekend (everyone home cooking, cleaning, dusting, burning candles, sticking hands in the tank, etc.). It seems to be getting better.

I do need to figure out how to skim the surface more... the water in my overflows is almost up to the top, the water doesn't "fall" far. I'm pushing quite a bit of water through, not sure I can drop the level down any.

 

[Kent E]

For the immediate, I'd ladle that gunk out of there.

 

[Gary Majchrzak]

as you might already know

as you might already know

it sounds like you need to increase the amount/rate of water being taken from the surface, Aaron. This isn't the same as increasing overall GPH going down the drains (although the two are related).

What length/diameter are your overflows (at the surface)?

Additionally- use pumps to direct water movement at the surface TOWARDS the overflows.

 

[DaveAngie79]

i have the same issues with one of my tanks that runs on an overflow
and about every 2-3 months i need to clean out the u tube and things start working great again, also having a pump blowing towrds the everflow box helps but does not prevent it from hapening cleaning the u tube is a must

 

[golf nut]

it sounds like you need to increase the amount/rate of water being taken from the surface, Aaron. This isn't the same as increasing overall GPH going down the drains (although the two are related).

What length/diameter are your overflows (at the surface)?

Additionally- use pumps to direct water movement at the surface TOWARDS the overflows.

100 percent correct.

 

[AaronReef]

Gary the big tank just has two "Megaflow" overflows. The problem seems to have cleared up in that tank.

The 75 has a single corner megaflow, but the returns are also in that overflow, so a small area around the overflow is clear, but the rest of the surface is maintaining a thick film.

I'm going to try a second return on the opposite side from the overflow and see if I can push the gunk down the surface skimmer.

Thanks!