Yup, that stuff will work. Don't skimp on the primer, that was my lesson learned.
You only need teflon tape on threaded interfaces. If these interfaces are under water (i.e. at your return pump) then you don't need it there either - because if you have a small leak inside your sump, who cares? (I'm assuming your return pump in internal to the sump - I can't remember off the top of my head your exact configuration)
In the DC Metro Area? Check out GWAPA