white film floating on surface of the water

[robr0924]

I bought a 55 gallon complete set up from a friend of a friend, several months ago. The tank had lots of calcium build on the top 3in" of the tank. It came with white and black sand, like that use in salt water tanks. Fluval 305 and a ehiem heater. I set it up several months back and have been letting it run ever since with nothing in the tank. Yesterday I went to put in some angels and when I lifted the lid i noticed a thick film of white scum floating. I was able to remove 50% by skimming it with a net. I have adjusted the outlet of the fluval to break the surface of the water and it is helping but some of the scum remains. any ideas what this scum is from?

The tank was always freshwater from what I was told.

thanks

[imagirlgeek]

I've heard of an 'oily' film on the water surface, but not 'white'. What kind of rocks and/or wood do you have in the tank?

I admit I'm not the best person to address this since I keep the water surface in my tanks agitated with powerheads and the filter's outlets so I really don't get anything settling on the surface. Have you tested the water parameters to make sure they are all in the healthy range?

[stevenallenbarnard]

do you have any air stones going in the tank? The first thing you should probably do is a water change if you haven't already, try to suck/skim as much of it off of the surface if you can. You defiantly need some surface agitation going like imagirlgeek talked about above. The surface is where most of the oxygen exchange occurs. heavy film on the water surface means that your water doesn't have as much oxygen in it as it could. a good air pump could help with this (if you need one but can't get your hands on one let me know, I have a couple of el-cheapos laying around somewhere.) If the cause is biological, then upping your water changes and adding more surface agitation should help a lot.

[robr0924]

thanks I have the fluval breaking the surface at the momment and will be putting a air stone on shortly. No wood in the tanks, just fake rocks that came with it. Testing was within safe ranges, but I'm going to do another water change. The scum is about 15% now much less then it was.

thanks for the input

[robr0924]

Today I moved the 55 gallon and 75 gallon into an extra bedroom, we are redoing the office floors so I had to move everything out. The 55 had been doing about the same, and the two 1" angels seemed to be doing fine. So naturally today I did a 90% water change, and moved the tank. Filled it back up and added stress coat and instant tank chemicals. Figuring they either make it or don't. I added and air pump and stone today as well. its been seven hours and everyone looks to be doing OK.

The 75 gallon I did a 98% water change because my daughter walked away while the tank was draining. I moved that tank rather quickly and stressfully and loudly. And got water back into it. I did lose one harliquin tetra, and one austrialian rainbow. Otherwise all is well.

Thanks again for the input.

crossing finger I don't wake up to a disaster of dead fish.

but she's happy.

[naps]

It's all about the surface movement...it's most likely protein film buildup. Airstone or point your filter spray bar up more, or add a HOB filter. I had this on my 55g for a bit. The white stuff would film up and sometimes actually foam like soap bubbles.

I added more surface movement to my tank and it's gone now.

[justdoit]

dont know if it applies but too much stress coat can look like soap scum on the surface.. I try to not add any water from bags fish travel in as some fish stores dump abunch in.. all for lots of water changes till you get a handle on it..

[jarrodaden]

+1 on surface agitation. I recently got a buildup like this in my wet / dry and I put a bubbler in there. I have had no problem since.

Due to problems like this, I have all my large tanks equipped with a skimmer or an overflow.