Hi everybody-I could totally use some help ASAP. I've had a 75g for years, ran it on a Fluval and skimmer, had tons of healthy coral and fish. About a month ago I upgraded to a 120. I put a sump in the basement. Huge skimmer in there, I have my water going through a sock with a bit of carbon in it, and about 40 lbs of rock. I have 4 powerheads in the tank, the lights I'm using are 3 250w MH (alternating), and 3 96w 420nm Actinic, and then the blue LEDS at night. When I had the smaller tank, all the corals were great, extending, feeding, growing. Then I moved them in the new tank (used a lot of my existing water BTW). Over the last 2 weeks all my corals are taking a nose dive. Even the huge leather I've had for 4 years died. My cabbage is going, the brain is almost gone, as are the hammers. Even the mushrooms are looking haggard. The fish seem to be doing fine. I've got 2 rabbits, a sailfin, 2 diamond gobies, 2 black perculas, bicolor pseudo, 2 yellow tail damsels, lots of snails and hermits. I run my lights about 10 hours a day and 2 MH at a time over the course of about 7 hours. No different than with my old tank. The temp is stable at 75 degrees. All my levels are at normal acceptable ranges. I add calcium and essentials, iron and other bits about once a week. I was the sock every other day. I'm adding about 5g of water 2-3 times a week to the sump. I have not done a water change yet. I'm about to have a very gray tank, I'm totally bummed I'm losing all the corals I've had for years. Ah, I feed seaweed 2 times a day in a lettuce clip for the fishies. They gobble it up, never noticed even a speck getting to the bottom of the tank. I'm not having any kind of algae problem. Anybody have any ideas that may enable me to save my corals before its too late? At this rate I think they'll be gone in about 3 days!