So what seems forever ago I posted that I had cloudy water. It started out as mostly a white clody, but quickly turned green. It got pretty bad.
The responses I got in the forums here were great, but none really worked. I tried to over-filtrate by buying another AC110 filter, I tried the H.O.T Magnum 250 with the micron filter, and all kinds of "clear your water" liquids.
NONE of them made a dent in the what was now a very green cloudy water. (i let each option run it's course for over a week)

So I looked back at some older posts and someone had recommended a UV sterilizer for any color of cloudy water. I bought the 9W Green Killing Machine UV Sterilizer from Amazon. It said it was only for tanks up to 55g, so I wasn't sure it would work for my 75g.

After 4 days I started getting a little worn out and beat down by the fact nothing had worked and this seemed to do nothing either. But I knew it was rated for a smaller tank, so I left it in there running.

Happy to say after 7 days the water is clear. I took the steriler out and did a water change and a week later it's still clear. Not sure what caused it (too many nutrients in the water?), so I'll keep an eye on it. But I knew that I wanted to get the problem at least temporarily solved and this did the trick. Hopefully it sticks. So far so good.

So thanks for the all advice, and I'm glad I finally have clear water to see my fish!

Make sure you have no nutrients in your tap water. Green water needs lots of light so make sure your tank isn't getting too much. If it happens again, make extensive water changes with Distilled Water; it should contain no nutrients or bacteria.

I would just leave it on and running. Some don't use them 24/7, others do. There is discussion on other sites from time to time that they will remove some added ferts or at least reduce their potency, but I'm not totally convinced. Some guys with planted tanks run them 24/7 and have no issue.

A UV sterilyzer is the best method that I am aware of to take care of green water, but I hardly recommend it because it is a cost. You can achieve similar results with a total blackout for 4-5 days.

Have you tested your water for phosphates?

I just kill the lights on my tanks (planted) and stop adding food. Clears up in a few days. of a couple of weeks at most.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden