Tank problems

[christyf5]

Hey guys,

So over the last few months, I'd say since about March, I've been having issues with my SPS. At first I figured it was a crab, and at that point it probably was. I could see little bits and pieces of tissue missing here and there from various SPS. They never had any problems with it and most of them recovered nicely and even grew a little. After removing the monster crab things seemed to be coming around. But in the past two months I've noticed that two of my millis don't have the best polyp extension. And strangely enough my frogspawn has been rather puckered up as of late. Could be some chemical warfare there? Who knows?

Anyways, in the past few months, I've noticed that more than just a few of my SPS have been actually receeding at the bases. Not just little bits missing anymore. Most of it was happening on one side of the tank. I had lost a piece of my tunze bracket and had to remove it from the tank, replacing it with a hagen 802 for what I thought would be a short time until I received the part. During this time most of the tissue recession/RTN/STN was happening only on one side of the tank, the side that was being fed by the Hagen 802. In an effort to correct this I returned the tunze 6060 to the tank siliconed to its mount. The tissue recession has not slowed.

I did have a few of the skeletons turn green (indicative of phosphate) and I added phosban back into my phosban reactor (I was previously running carbon in it). Since then, the skeletons remain white but they are still receeding. The majority of the SPS have taken weeks to die, and they've all been frags. Looking really hard at the tank now I can see that I'm starting to lose colonies now and its picking up speed.

Last week I tested my water for nitrates (5-10ppm) and phosphate (0ppm/trace). Salinity is 1.025, ph is 8.2, calcium 410, alk 10.8, Mg 1440. Everything seemed fine but I did a 30g water change and have another one scheduled for tomorrow.

Now I'm starting to suspect my refugium, after all it has a sandbed in it. Any thoughts??

TIA
Christy