Ok, I've been changing the water for two weeks (50% and then 20% every other day), removed most of crushed corals. Now nitrates are down from 150 to about 5ppm using my test. Salifert Tests are coming in couple days. Corals look much better now, brighter colors. The acropora that I fraged finally becomes green (instead of brown). I think it's good for two weeks? Now I have to get rid of xenia, it's taking over my tank.