Oh No! Brown film on surface of water!

[nickbuol]

About 2 weeks ago, we started seeing a light brown "film" on the surface of our 75 gallon FOwLR tank. The tank has been up and running for about 7 months now, and all along the way people on this board have been saying that we have been doing really well. The only 2 problems we have hit have been red algae (possible low circulation, going to get a couple for powerheads to help) which I treated with a red slime algea remover, and now this brown stuff. It doesn't seem to be harming anything at this point, but it sure doesn't look like a good thing. I have had the powerheads pointed down a bit and towards the middle since I was using airstones for some water movement and surface agitation. The air pump died (it was the only used part of the setup) and I have yet to replace it, so I pointed one of the powerheads towards the surface to help, but the brown is still there.
On a related note, our powerheads are shut off every night when the lights go out. I had read that it gives the fish a break from the currents while they sleep. Should I leave them on? Thank everyone.

 

[nickbuol]

Thanks. I will change them to stay on tonight, and make some "less flow" spots as well...

 

[beth]

I can't believe I just read that ...........what bad info that was!
The brown stuff is likely diatoms, or hopefully that is all it is. Considering that you are turning off a part of your filtration system at night, who knows what kind of problems that may have caused. However, if it is diatoms, this is unsightly but not fatal. Clean them up as much as you can, check your water for phosphates [phosphates is a food source for diatoms]. If your phosphates are anything more than negligable, then find out the reason you have phosphates and fix the problem, and, finally, LEAVE THE POWERHEADS ON!

 

[nickbuol]

I think Beth meant that the bad advice was the one about turning the powerheads off at night to give the fish a rest....

 

[janice]

How important are the powerheads? I have a protein skimmer and a canister filter - both create currents. I've heard/read both that they are a must and that they are optional. My LFS said the protein skimmer should be enough - opinions? (55g, LR, fish, inverts) And please don't flame me here... I can only know what I read/hear and my resources are limited.

 

[nickbuol]

Janice, we have a 75 gallon using a Magnum 350 canister. The water comes back into the tank via 2 powerwheels and the standard "tube" that comes with any canister. We also have a Prism skimmer, and 2-AquaClear 3000 powerheads (260 GPH each).
I am not sure how much water the skimmer moves, but the canister and powerheads move about 870 Gallons Per Hour in our 75 gallon, or the water is "changed over" 11.6 times an hour. With that in mind, we have still had 1 red slime algae bloom and the brown film on the surface of the water (that this topic started off as). Both caused by lack of water flow. I have now set it up that the power heads are on 24 hours a day now and the water it very clear. No more brown film, etc. I still have 2 more powerheads on order, but they are going to be put in for extra daytime circulation.
So, are powerheads a must have? Maybe not, but I have seen a great inprovement by using them. And heck, they are pretty cheap when you think about it. Way cheaper to buy one or two than to cause poor water quality for your fishies....