What is it with 90 gal tanks and green water??
My own "green water" thread is unavailable now, but had some real doozies for pictures, you couldn't see 4 inches into the green murk.
I upgraded to a Turboflotor 1000 skimmer, put a borrowed UV filter on a slow powerhead, added carbon in the sump, added floss, changed the floss and carbon often, ran Kent phosphate sponge in a Fluval, reduced the photoperiod, ran a micron filter, and still had to remove my Tang as it was suffering.
Oh, and I put in a couple of donated clams - they love the stuff. After adding the UV filter and second phosphate sponge, things started to clear up. Lost a couple of corals but no fish. The clams grew...
Good luck with your green!
