need help!

[cbaier1206]

I have five sps corals including 3 acroporas and 2 milleporas. All are showing great color, growth, and polyp extension. The problem is that one of the acros starting turning white from the base and spreading upwards about a month ago. Here in the last week now all three of the acros are doing this, and tonight I could swear that one of the milles is doing it now also! I also notice that there are hundreds of these little white circular things attached to the rocks and the back walls of the tank...don't know if they have anything to do with this.

My water quality is this:
Salinity: 1.024
calcium: 430-450
alkalinity: 3.2-3.3 meq/l
nitrates: 1-1.5 ppm
phosphates: 0

I feed the fish and the corals with the same mixture every other night which includes Brine shrimp, rotifers, oyster eggs, phytoplankton, and cyclopeze.

I run a protien skimmer and a uv sterilizer 24/7, the skimmer pulls a good amount of junk out of the water and the sterilizer i run because my purple tang started to get ich and running it has fixed this.

My light cycle:
ON
9:30 2x24w actinics
11:00 150w 20K MH
1:00 150w 14.5K MH

OFF
7:00 150w 14.5K MH
9:30 150w 20K MH
11:00 2x24w actinics

Any help or suggestions would be grealty appreciated!

thanks

Chris

 

[cbaier1206]

sorry, forgot to add that this is a 56 gallon cube with a 25 gallon sump, and I am running 4 powerheads inside the tank for proper flow. This tank has been up and running now for about a year without any other problems.