[Alex123]

Ok this is drastic I tried black out for 3 days for my 20 and 10 gallon aquarium and the green water didn't change much. I know I read the part about doing it for 5 days maybe next time. However I did notice my anacharis grew 5-7 inches amazing! Anyhow, since my aquarium is small I decided to change pretty much all the water accept an inch and half at the bottom so I don't have to move the community fishes. It didn't take too long. No one suggested changing 90+% of the water. Anyhow, we'll see if this fixes the issue or not. From what I have read, the nutrients that induced the green water have been used up by the algae but the green water will remain unless killed or removed. Well this seemed like a straight forward way of doing that by removing most of the water. I don't know why this is not suggested as an option. I read it cause undue stress to the fish. I highly doubt that since it's the same water they are used to but cleaner. Anyhow, I hope the water will remain clear. I'll post back later.

 

[Alex123]

Ok just want to report that the water is under control after removing most of the water. The remaining green water I didn't remove caused the water to be a little bit hazy. But for the last 5 days it looks to be not getting worse. I have decided not to let it have direct sunlight currently, my tank is planted. If the water becomes crystal clear, I will open the blinds and let direct sunlight in. Actually my 10 gallon is almost crystal clear and my 20 is slightly hazy. It seems to be like than when I first set it up too as I can recall. It never was crystal clear like my 10 gallon.

 

[Alex123]

Another update. The water remains slightly hazy not clearing up. I can see from one end to the other but the haziness is just flat out annoying. I don't have any filter except a water pump to circulate the water. I have finally solved my green water problem though and this should be called the simple cheap method and don't have to wait for this dang 5 day blackout or expensive uv filter. I ran it for 5 hours and the water looks like doing a 80-90% water change on a green water tank. It's not crystal clear though. I'll see after 24 hours.