saabtech here's what I do:

I have a small hang on filter for the 10 gallon tank. Inside that filter is a sponge. When the QT is not in use I keep that sponge in my DT sump.
When I set up the QT I fill the QT with 10 gallons from my DT rather than make fresh saltwater for the QT. (Obviously I put 10g of fresh saltwater back into the DT ;) - a water change! lol)
Hook up the HOB filter, add the sponge from the sump and it's ready to go.
Right now the 10g is in the garage. I don't have it set up all the time because it looks so cluttered to have an empty fish tank just standing around.

Sorry I have no idea about tangs!