I have set up a freshwater tank at school for a research project. This tank is set in a display area where sunlight is on it most of the day. I am having problems controlling the algae. I have tried small daily water changes and using Algefix, but i can only do this for a few days at a time before stressing the fish out. The only fish in the tank right now are a Longnose Gar and a Spotted Sunfish. Any solutions?

welcome to the forum!

The problem in this situation is the sunlight. direct sunlight is real strong and will lead to rapid algae growth. The only way I can see this fixed is to move it out away from direct sunlight and grab a bunch of snails. If you want to simulate sunlight, I would use a desk lamp with a bulb that is rated for aquariums because they have the right Kelvin(light's temperature)

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36 Gallon Saltwater reef tank
Ocellaris Clown, Scooter Dragonet, sandsifter star, Decorator crab, emerald crab, coralline snails, blue leg hermit crab, and horseshoe crab.
Zooad's and shrooms
40 pounds of Live sand, 20 pounds of LR

Hello elasmo...

I thought about the health of the fish, before the algae issue. Water temps must really change during a 24 hour period. Are you researching the affect of temperature changes on the fish? Am surprised you have any fish still alive in the tank.

Small water changes will have little affect on the algae growth. The algae I'm familiar with thrives in water that's high in phosphates and nitrates. Only large, frequent water changes, in the 50 percent range will keep these nutrients to a minimum. I also use the small, brown snails usually available at the local pet shop and float a lot of Water wisteria and Pennywort to complete with the algae for the available nutrients.

B

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Low Tech Water Building Keeper

The building the tank is in is somewhat climate controlled. The tank stays any where between 21 - 24 C. Right now the tank is just set up as a housing tank, used for husbandry research. Phosphate and Nitrate levels are fine. The tank wasn't taken care of over the winter apparently, so the red algae took over. I cleaned the red out and the green took over in the water column. Im not having problems with growth on substrate. My next solution I was going to try was to introduce Marimo Mossballs. I was wondering if anyone has had experience with these? I used the small daily water changes and algefix method on a SW tank right next to the freshwater and it cleared it right up. But I can't seem to tame the FW. And no worries, the 2 fish have been moved to another tank for now.

I was having some difficulty with algae when I was cycling my tank. I actually wasn't looking to get rid of it at first, but I was looking for something to fertilize my plants with and I came across Flourish Excel. If you have live plants in the tank it will fertilize them and it will combat algae as well. The reason is that it supplies carbon for the tank which I read somewhere combats algae. I am actually no longer using it for my plants, but it did get rid of all of my algae. Granted my tank doesn't get any direct sunlight.

A 500ml bottle treats 100 gallons for 1-2 months. At least that is what it says on the bottle.

If you have live plants it can't hurt to try.

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Hello again e...

I have the Marimo Moss in a couple of tanks and got them as a curiosity. I move them and rotate them every so often to keep them relatively round. Apparently, if you don't do this, the moss will attach to rocks and form a type of carpet, but I don't think they do much to control other types of algae, if that's your aim. Might just grow over the other algae forms. I understand it can be broken up into smaller pieces and will eventually grow over stones and such, but that takes some time, it's very slow growing.

B

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Low Tech Water Building Keeper

Any way you can cover a side or back where the direction of the sun is? You could easily get posterboard and cut out sections of it to block the light. Would work well if it were getting it from the back.

You'll never control the algae with the sun beating on it and algae chemicals are pointless and dangerous to your fish.