Mark I was asking you if this was slime algae you have.
I re-read your post though, unless you want another tang one thing I can recommend that will make this stuff curl up and die is erythromiacin. When I first started in the hobby Sharla told me about using this in a very very small amount. That stuff just died immediatley. I never had an issue again.
The only draw back is it can bug your beneficial bacteria a touch but wow does it work. I have some human stuff that I keep to give you an idea when I moved stuff to my 3 gal and disturbed everything, I had this starting so I opened a capsule and took out 3 bead of this and zapped it all, never had an issue since then. So I have used it twice in a new setup and never had a problem with it coming back again.
Just a suggestion as appose to the fish unless you would like a new tang. AJ's has a tiny blue hippo in the front tank across from the till. Watch out for their rock though, lots of aptasia in there.
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Bugsy.... 
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