Algae problem...

[ConchRepublic]

I recently started working at the local Department of Environmental Protection station near where I live. I was placed in charge of taking care of the 2 250 gallon tanks they have set up. One tank had a major algae problem. I am not sure what kind it is (pictures below). It is all over the tank and has killed off all of the real plants and is slowly killing off the fish. The person who was in charge before me said they took everything out, pressure washed it, bleached it, completely changed the water, and put new bottom substrate in. The algae apparently came back and it refuses to leave. We've spent a day literally shoveling it out and it started to come back before we even stopped. Currently there are only about 4 fish in the tank (large mouth bass, bluegill, warmouth, and a large pleco). I don't think it is coming from the water system as the 2nd tank does not have any algae in it.

Any help in removing this?

http://i145.photobucket.com/albums/r221/conchrepublic101/DSC00037.jpg
http://i145.photobucket.com/albums/r221/conchrepublic101/DSC00038.jpg
http://i145.photobucket.com/albums/r221/conchrepublic101/DSC00039.jpg
http://i145.photobucket.com/albums/r221/conchrepublic101/DSC00040.jpg

[Alfcea]

Hmmmm.... what is the cleaning/maintenance schedule of this tank? Is it slimy and smelly? I'm not sure, but, if it is killing the fish it could very well be blue-green cyanobacteria... You might need to treat with erythromicine...

Any more details we should know about?

[OscarFan]

im going to say it has to be your water changes. You should be doing 25% weekly.

[W_Oz]

Looks like Cyano to me too. If it were my tank I'd look at the water quality and try to either dose the tank to around 10ppm of NO3 or schedule water changes to keep around 10ppm in the tank. I'd also look at the filter arrangement for that tank especially and see if there were a way I could increase the DO and water movement through the tank.

Cyanobacteria normally only shows up with low DO (Dissolved Oxygen) and either too much or too little Nitrate (poor water quality or the water is too "clean" but then you'd find it hanging out near the surface and not on the gravel). I'm going to guess that the former is more to blame than the latter, UNLESS both 250's are identically setup, then I'd say water quality is the big culprit.

So, yeah, clean it, plant it, get that water moving, and save them fishies!

I'd also look at the lights and see when the last time those were new was.

[Dave66]

I quote myself:
———
"CYANOBACTERIA

Blue-green algae isn't algae at all; it's a photosynthetic bacteria. Cyanobacteria is also toxic to most fish and it also consumes Oxygen, meaning a full-blown invasion of Cyanobacteria can suffocate fish.
It's also a slimy, smelly thing and many people find it disgusting.
It almost always appears when the tank has either a short photo-period or low lighting.
The solution is simple, but counter-intuitive.

Increase your light. The more light you have the less likely you'll run into Cyanobacteria. If you lights are already bright, run them longer. If you have one or two 40-watt tubes, add another and run them 12 hours a day. Cyanobacteria is primitive enough it can't assimilate bright light.

Bright light and manual removal will beat Cyanobacteria every time. Thankfully, Cyanobacteria doesn't bind tightly with solid surfaces so siphoning usually gets most of it.

So if you run into Cyanobacteria in your tank, light it up and suck it up. May take some time to beat it totally, but it can be done.

Interestingly enough, Spirulina, present in many fish and people foods, is also a Cyanobacteria."
———

From my algae primer stickied at the top of the algae forum.

Dave

[ConchRepublic]

Thanks for all the advice. Both tanks are exactly alike besides the fish. The filtration is a paper filer system that then goes to a sponge filter (I'm trying to get them to switch to a bioball system instead of sponge}. I'll check the lights to see if they could be changed for brighter lights and make the timers keep them on longer. We do a 25% water change although it's bi-weekly, I'm sure it hurt the bacteria because small spots start turning brown, so I'll start doing it once a week instead of bi-weekly.