Clear Water.

[Joshwainwright]

How can I keep my water clear?
It goes cloudy, then green.

 

[OldMan47]

I am going to guess that you have your lights on at least 10 to 12 hours a day or that the tank is near a window where it can get some sunlight. Green water algae, what it sounds like you are describing, needs a lot of light and some nitrogen to grow. Unless you do 50% or bigger daily water changes, chances are good that you have some nitrogen and cannot get rid of it at least in the form of nitrates. That leaves light as the thing that you can control.

 

[Joshwainwright]

My tank is next to a window...

 

[OldMan47]

You might want to try blocking the back and sides so that less light gets into the tank. You obviously don't want to block your view of the fish.

 

[Joshwainwright]

I'll use printer paper for now but over time I will try think of something else.

 

[HCpetraitis]

If what Oldman says doesn't work, (no offense old man) they have water clearer that you can buy at most LFSs

 

[OldMan47]

I am sure that you are basing that on your experience HC but I can't keep green water alive unless I leave the lights on 24/7. As soon as I back away from full time lighting, the green water vanishes in my tanks. I have never had a real green water problem because the only green water I have seen was intended to be food for my daphnia culture. I finally gave up the culture because I couldn't grow the green water fast enough using artificial light.

 

[MHunt]

What's the stocking level in the tank. It could be that the fish are producing more waste than the tank can handle so the excess nutrients are allowing the algae to take hold. I've had green water take hold where I've removed plants from a tank, the algae then has more nutrients to itself and again you get a green water bloom. You could try adding some fast growing plants, Amazon sword etc to use up some of the excess nutrients and inhibit the growth of the algae. It's a balancing act I'm afraid, and you'll have to try a variety of things to get it under control. You may also find that in time the tank gets to a balance itself and the algae just stops growing. Until then there are products out there to help remove the algae, but you're only treating the symptom, not the cause.