green water means your tank has too much nitrate. Did you check for nitrate level in your tank? Also, green water is still way better than cloudy water which can be a bacteria bloom that shows your tank didn't cycle through enough. I want to say put water plants in you tank, but your fish would probably tear them up. Try limit light, do frequent water changes 15-20% every other day, and see if that works, and also, put more charcoal in your tank.
Good luck, and tell us about the tank.