Green water in hospital tank

[Franky099]

I have a 10 gallon hospital/quarintine tank.  Its just a 10 gallon with hood, filter and heater.  No gravel or anything....just tank and water.  The water WILL NOT stay clear.  Within a few days it turns green....I mean really green....you can only see an inch or two through the water.  I dont get it.   It used to be a breeding tank for bettas.  Thats the first time it happened...when I was trying to rear fry.  when they were big enough I moved them to another tank and used that as a hospital tank.  I cleaned it well and restarted it.  Some of my females got ick so I put them in there to recover.  When they were healthy and returned to their tank, I cleaned and started over.  Now I have 2 sick gouramis in there.  They ahve been in it for 3 days now and the water is already getting murkey.
WHATS THE DEAL?!?!?!?!?!?

 

[Matt Nace]

It will be cloudy after you clean it. I am guessing you clean the tank, walls, filters, ect? You lose bacteria there. But green water??

How long is your light left on?

I don't think it would be nitrAtes causing the green water, you just put those in there and you know not to overfeed.

What do you put in to treat the sick?

 

[Franky099]

lights are on 8-10 hours.  I havent treated the tank yet because I wanted to see if it still turned green...and it did.  The treatments I use turn the water blue anyways....not green!  

 

[Matt Nace]

Very intresting. Green water is free-floatting algae. Too much light along with nutrients in the water cause it to bloom.

Try a waterchange, and leave the lights off for at least 24 hours. What else is put in the water?

Are your NitrAtes high?

I wonder if it could be something in your tap maybe?