Algae in tank water

[lmag]

I have had a 10 gallon tank for almost a year, and have not been able to stabilize it. Right now, the problem is green water. I've tested the water, and the ph, nitrite, nitrate and ammonia levels are all fine. I took out all the gravel, and only have marbles in it. I replace about 20% of the water every week, but the water is very green. The algae doesn't seem to grow on the walls as much as in the water itself. I have no plants. I currently have 3 neon tetras in the tank, and one algae eater - not sure of the name since my husband just picked him up. I'm ready to replace all the water in the tank, but don't want to risk these fish. Any advice/help would be greatly appreciated.

 

[Fishyfanatic]

What you have is suspended algae. Does the tank receive direct sunlight? How long are the lights on per day? Have you tested for phosphates? How much are you feeding on a daily basis?

Green water can be caused by high phosphates, over feeding, too much light, or direct sunlight.

BTW- Welcome to AA!

 

[lmag]

The tank doesn't receive direct sunlight, and we used to have the lights on for about 8 hours per day, but the bulbs are out so the lights are off all the time now. I haven't tested for phosphates, and we're feeing a pinch every morning. I'll leave the lights off for now. Do you think I'm feeding too much? Can I get a test for phosphates at a pet store? Thanks for the quick reply.

 

[QTOFFER]

The good news is that green algae is harmless to the fish. The bad news is that you can't see your fish, and the algae eaters won't eat it.

Excessive light and/or phosphates is the most common cause of green water. Did you recently disturb the filter or stir up dirty substrate recently? These can release phosphate-rich gunk into the water.

Aquarium Pharmaceuticals makes a phosphate test kit. Several lfs near me carry it, so it shouldn't be too hard to find. You should check your tap water for phosphates or call your water company for this info.

The following will get rid of the green water, but won't necessarily prevent it from coming back if you don't find and fix the underlying problem:
You do a 50% water change and cover the tank completely with a heavy towel so ABSOLUTELY NO light gets in. Leave this for 4 - 5 days. Don't peek or even feed the fish during this time - they will survive just fine. After 4 - 5 days, uncover the tank and do a 50% water change.

Good luck!

 

[lmag]

Thanks so much. I'll find out about the phosphates, and we'll try the water replacement and covering the tank and see what happens.

BTW, we did recently have a filter malfunction and I replaced the faulty one with a new one, but I we already had the algae problem before any of that started. I think we have a really good filter now, so if I can just stabilize, we should be ok. Here's hoping!

 

[Jarred Darque]

There are other options as well, but they cost money, Diatom filters will physically remove the green algae, or a UV sterilizer will kill the algae as it passes under it in a special filter.

 

[SeymourFRESH]

i don't know anything about diatom filters but a UV sterilizer will also prevent the algae from coming back