Welcome to AA
. Is it a fresh water tank? I've never seen the "green water" problem in a salt water tank. If it's fw
then turn the lights out and keep it out of the sunlight for a few days. After it clears up then don't ket it get in the sunlight again. Of course if it's a "got sunlight on it and no way to fix it" then I think a product called Alage Fix might do the trick. My 55 is in direct line with the front door, and someone is always fanning the door so I have to use alage fis to keep mine clear.