SPS Corals losing color (browning)


If the sps lose their color and now they look brown, what is the main problem? Some of my colonies turned brwon and I cant find out why.
I have 125g/ 55g sump. 3MH, two 250w on the sides with 20k bulbs and 1 in the middle with 10k bulb.
Ph 8
specific gravity 1.027
po4 0
amonia 0
nitrates 0
nitrites 0
calcium 500
kh 7

Craig Lambert

Premium Member
Phosphates will cause them to brown out. Do you have a high bioload and feed alot? Is your filtration sufficient? I see a couple of things in your parameters that I would change. You might slowly drop your SG to 1.025, or maybe 1.026. I would also raise your Alkalinity level to the 9-10dKH range, and try to get pH up to 8.1-8.3. How long has the tank been up?