Can we come back to HKGAR's issue for a bit?
HKGAR, lets talk about your refuge, it has grape caulerpa in it and you have only cut it back one time in 2 months?? That should grow enough (with proper lighting) to cut back once a week or so. It MAY be the source of your problem, look at it carefully, is any of the caulerpa clear or white? If so cut all that is that color out.
Do you have any LR, LS in the refuge?
Have you put any creatures in the refuge?
A refugium is a great addition to any system, but it needs to be maintained as much as your display tank. Check things out and please repost..
I know that this thread has gone away from your problem and would like to try to help you further..
Bill