I have a 10 gal
aquarium with sand substrate about 4 months old tank. It has 6 guppies (adults + babies) - all doing well.
The moss started growing very well initially, but for the last 2 months I have green algae problem which makes the water green. The moss now looks dark green and is turning brown in some places. Frogbit does not survive in this tank. (It is growing like crazy in my other tank).
I do not fertilize this tank and do weekly 25-50% water changes (depending on how much green algae I have). Feeding fishes once a day and I ensure there's no food left over. I added nerite and 3 RM snails.
I also tried keeping lights off for few days after major water change. But when I turn it back on, by end of the day, the water turns greenish. Plz see attached picture.
Any suggestion how to get rid of green algae?