Green water

[benboarder]

So my sister has a 15 gallon tank with a 3" cichlid and a 1" pleco. The tank is almost 7 months old and for the last month the water is a dark green color. I know this is algae in the water but its not getting any sunlight. There is a T8 light on it at 15 watts. She dose a 1 gallon water change every 2 weeks. Nitrates are about 20 ppm. She has never needed to clean the glass. Dose she need a new light or more? Thanks for any help

[Jacobsdad09]

Is she feeding alge wafers? I did that for a bit and had a slight green tint to my water and then stopped and the green went away

[benboarder]

No she just bought the pleco 3 days ago to see if that would help but i told her the algae is in the water. I dont know why this is. Should we add more light ir a few days without light?

[TinyGiant]

they make stuff that will clear the water of suspended algae.  the name of it is slipping my memory right now

do you have a power filter on the tank?

[TinyGiant]

UV sterilizer would kill it too

[benboarder]

Yes there is a HOB one rated for 15 gallon tank but will be swapping out with a 40 gallon HOB

[gotareef]

the filters wont work on it, its algae in the water.

wrap a blanket around the tank so no light gets in for 3 days and the algae will be gone

get an aquaclear hob filter for the tank and buy a bottle of amquel plus