Gray film on top of water???

[iannozzi]

Just noticed that I have a fine gray film on the top of my tank--almost like an oil? Everything is thriving, water very clear. What is this film? I am currently not protein skimming--was advised by GARF to not skim for a month to allow my tank to seed from their Grunge. I find my BTA silversides--is the oil-like film the result of the BTA digesting and excreting waste? With this being said, should I start skimming again? I am on the fence with this--I change 2 cups of saltwater every day--approx. 3.5 gallons a week--its a 29 gallon tank--I have xenia, BTA, Brain Coral, and a platygyra. Should I skim or not??? I need to do something to get this film out???

[Salamander]

Sounds like dissolved protein forming a film on the surface. Do you have an overflow? That might help. Changing 2cups of H2O does not sound like it would be of much benefit IMO. I'd consider doing a bit more of a change/week. I'm not really sure about not skimming because of GARF GRUNGEwith an already established tank. Get in touch with GARF and ask them how much of the benificial bacteria etc skimming would remove.

[iannozzi]

You think I should do more than 3.5 gallons a week--my tank is only 29 gallons--3.5 is over 10% a week. I have a remora skimmer--and I turned it on --so I'll keep it on until the protien film dissapates. J. Sprung seems to advocate protein skimming in a limited capacity, not 24/7 especially with xenia in the tank.

I see you have a remora--do you like it--how do you handle the micro bubbles?

[Salamander]

If you're having difficulties with dissolved organics, then larger water changes might help. The amount you change out really depends on bioload, feeding etc. 2 cups a day just sounds miniscule to me. It might be ok and it is a decent percentage.

I'm not a big fan of my remora to be honest. Its the next to go. I have it in my sump with several baffles to pass by before the fuge and then into the display so I really have no bubble issue. I do have Remora's prefilter/bubble trap that I'm not using and would be willing to part with for a little $. I think it would help some but I'm not sure how much. Search for some reveiws.

HTH

Mark

[GARFVolunteer]

<a href=showthread.php?s=&postid=6767799#post6767799 target=_blank>Originally posted</a> by iannozzi
Just noticed that I have a fine gray film on the top of my tank--almost like an oil? Everything is thriving, water very clear. What is this film? I am currently not protein skimming--was advised by GARF to not skim for a month to allow my tank to seed from their Grunge. I find my BTA silversides--is the oil-like film the result of the BTA digesting and excreting waste? With this being said, should I start skimming again? I am on the fence with this--I change 2 cups of saltwater every day--approx. 3.5 gallons a week--its a 29 gallon tank--I have xenia, BTA, Brain Coral, and a platygyra. Should I skim or not??? I need to do something to get this film out???

This film can develop for many reasons. Before I had an over flow on my tank I use to get it all the time whenever we cooked meat. There are a few ways to get rid of it.

The first way is to add an air stone at the water surface. The stone will break the surface tension and the film will mix in the water. The big problem with doing this is the slim mixes back in the water and you have a potential salt creep issue using the air stone.

The second way is to add an overflow that will skim the water off of the top of the tank and send it down to a sump. If there is a refugium or skimmer in the sump it will help[ remove it.

The third way is to break the surface tension by directing a power head output towards the surface.

We have a 60 gallon lagoon tank that gets this film a couple time a week. Since this tank has very little current by design and no chance of putting a sump in to skim the surface I resorted to a method that Leroy Headlee at GARF taught me about 7 years ago.

1. Grab a few sheets of printer paper.

2. Lay a sheet of paper on top of the film and immediately remove it. You will notice the film was attracted to the paper and the side of the paper will be covered with the film.

3. Repeat with a new sheet of paper until you have removed all the film.

Some will tell you this is a nutty way to do it but if you think about it, it makes perfect sense. Until the paper becomes saturated with water, it is hydrophilic(loves water). Since the paper is immediately removed it remains hydrophilic.

Also about the only way I differ from GARF's approach when setting up a tank is I add the skimmer on day one...

Thanks,

Scott

[Jive Turkey]

Yeah that works. I remove it with undyed paper towels on a tank w/o surface skimming, my 20gH.
I think its mainly DOM, dust, and food oils.

[JmLee]

some more surface aggitation helps aswell. I.E. Powerheads. Plus it will help with gas exchange.

[smcnally]

Some sort of surface skimming would help. Did you just set this tank up? I wouldn't recommend a BTA in a new tank if so. You could also try to cut back on the BTA feeding. If you have sufficient lighting you don't need to feed it often at all. I haven't fed mine in 6 months and they are thriving. Also, I have to disagree with "Salamander" on the water changes. Dr Randy Holmes Farley did a studdy on the effects of large bi-weekly water changes and small daily water changes. He found they had pretty much the same end results. He had the data to prove it too. He showed a graph of the effects of a bi-weekly (15% per change) 30% change done monthly over a few months next to a graph of a daily (1% per change) 30% change done monthly over a few months. The only difference was the drop of levels in between changes. The end results were almost identicle.

[reverendmaynard]

I agree. RH-F uses the "small change every day" approach in his own tanks.

When doing those small changes, push the empty cup down into the water and then slowly tilt it so that the surface water flows down into the cup. If you do that everyday, it shoudl keep the surface relatively scum free.

[sean48183]

I use a prizm pro deluxe with a surface skimmer right in the middle of the tank with 2 maxi 1200's in each corner directing this crud right into the skimmer. Keeps surface crystal clear.