marine velvet

[lpsreefer]

My predotor tank just got marine velvet. the first time I didn't qt a fish. so upset I lost my masked swallow angel and hogfish. my trigger has it but seems to be okay he is in qt now.
I was just wondering what the sereval rate is? he still eat and swims around like nothings wrong. the other two stop eating. they didn't even last 12 hours where the trigger has gone on for over a week.
second question if I keep the tank fishless and rub a uv for 8 weeks well I get it out of my system? or do I have to qt all my corals and live rock? and scrub te tank down?