I am someone who has read so many GHA horror stories that I have done everything I could not to get it. Well, over the past 3 weeks, I have had a pretty bad case of GHA. I'm going to detail my post here as much as possible to answer questions up front, but if I'm missing something, please let me know. The GHA actually started the day after I added about 10 lbs of live rock and some GSP that never opened in my tank. I have other corals that do fine, and I took the GSP back to the LFS after it didn't open for a week. So, I tested my water, and tested some more. Things haven't deviated so much, and this is where things are at right now and pretty much have been for 3 weeks, except for my mag level, which I've been slowly increasing. Ammonia -0 Nitrite - 0 Nitrate - undetectable Phosphate - undetectable Alk - 9 dkH Calcium - 450ppm Magnesium 1400-1600 (where I started to where it is now) Salinity - 1.026 Temp - 80F My nitrates on a low range test kit were .10 three weeks ago, but now are undetectable. I run an oversized skimmer, I run cheato in a fuge, DSB, 70 lbs of live rock, and limit my feedings to one cube per day. My fish stock list: 1 Dwarf False Lemonpeel angel 1 Sixline 1 Mandarin Dragonet 2 bar gobies 1 dart goby 1 firefish goby 1 yellow watchman goby 1 yellow clown goby I have about 40 small blue legged hermits, 10 or so scarlet reef hermits, and four emerald crabs. I have a few stomatella and other critters that showed up on the LR. I have scraped as much GHA off the walls as possible, and do this just before changing about 15 gallons of water that I wet skim over about a several hour period and replace with salt water that is mixed with a power head for 12+ hours using measured 0 TDS RO water. I change at least 10% a week. I have opened an outside door near the tank to let in oxygen and CO2 out. I have a Magdrive 18B return pump agitating the surface of my water. I also run two Koralia K4 powerheads for flow. My lighting is 6 x 54W T5's. I have all but one new bulb and I'm waiting on my LFS to get bulbs in. I run my blue bulbs for 10 hours and my daylights for 8 hours. Now, this is my theory about GHA: GHA has trapped nutrients in it that will remain in the tank until all of the GHA is removed. It is not easily starved out as long as some of it is there, as it dies off, it just allows for more to grow. I have noticed some die off, but as soon as it looks like the coast is clear, it comes back in full force. I am starting to think about getting a sea hare to eat it all then trading/ giving the sea hare back to my lfs or someone who can support it. Any other ideas? THANKS!