Green algea and Brown surface water..

[MarineFlake]

First of all hiya. I have been posting on some other sites but after lurking a while here, this seems to be a little more mature crowd. I have couple questions. I have a 75g reef tank that I moved from previous owners home to mine about 3 weeks ago. Since then everything has seemed to recover and stabilize. However, this last week I have noticed some interesting hairy green algea and the surface of the water in the tank seems to be covered with a dust like film. Its too fine to be scooped out with a fish net and is almost oil like. When I dip a hand or bowl into the water, it comes out covered in this 'film'. Anyone got a clue for me? Also, the green algea, seems the more I mess with trying to scrape it off, the more it spreads..??

Thanks!

 

[jackdp]

Sounds like you could have hair algae. What kind of filtration do you use and is there a skimmer? Test your water for nitrates and phosphates and if either is detectable try to find the source and eliminate it.

The surface film is dissolved organics. They are present in most tanks and settle out on the surface. The best ways to limit them are with good surface agitation via a powerhead and a surface skimmer attachment for either your protein skimmer or a power filter. GAC will also help. Or you can keep dipping your arm in the tank and removing them

 

[Gauge]

Just FYI, the film on the surface is frequently referred to as an oil slick and as far as I know it's neither a serious problem nor a sign of a serious problem. They seem to be more common and thick in a topless tank. I think that dust figures into it in that case. Mine got much worse after I removed my glasstop.

 

[MarineFlake]

I do have a HOB protein skimmer which was out for a couple days due to the air line being clogged by what I think was salt. Filtration is basically a wet/dry setup. It is water out of the overflow dumped over rock which sits on top of a piece of filter media. Its is them pumped right back up to the tank. The water itself is crystal clear, but the surface still brown. There is in fact no top on the tank and never has been though I have only had this tank for a little over 3 weeks. As for the algea, the more I dink with it, the more it seems to spread, so I have stopped trying to scape it off.
-Paul C.

 

[MarineFlake]

UPDATE:
I turned on the HOB power filter and overnight the water on the surface is clear. As for the algea, I cranked up the De-Nitrator and plan a 10g water change to see if it makes a dent in the green hair algea thats taken up residnce. Though it seems that the Xennia is giving the algea a run for its money as Xennia apparently doesn't take to kindly to anything trying to impede its own ability to dominate any surface! Yay Xennia!

-Paul C.