Tank problems

[Jason McK]

Christy,
Sorry to hear your still having problems.
A couple of things I've been finding, A lot of my SPS are causing there own demise. They out grow the flow in the tank, or another SPS grows and cuts off flow to a part of another coral. This allows detritus to settle and either kill the coral or allow algae to grow and kill the coral.
Not sure if this could be a factor in your case. But That is what I'm dealing with now in my 75G.

Is there any way you could isolate your refugium? If you could I would stir the crap out of the sand and let it run through a mechanical filter for a couple of weeks. This should clean out the sand while still getting the benefits from it after you hook it back to the main tank.

I still feel your base tissue loss is a flow problem. you may want to change your flow around drastically, by moving power heads to very different locations for a while.

Just a few thoughts
J