How much flow do you want in the tank, and how much of it being created by the circulation pump (and moving through the sump, vs internal prop pumps or closed loop)?
is the sump under the tank, or in the basement? how much head pressure has to be overcome?
what size is the drain from the tank to the sump one pipe or two how much is you skimmer capable of prosessing???
I run a Quiet One 4000 on my tank.
it came with the tank.
is it really quiet.
they are cheap to replace.
only runs about 50w.
compact size
I think 1000 gph is plenty thru the sump, i also run a couple modded MJ's for flo.
I may even get a 2nd one cuz my skimmer pump is LOUD.
Peter, I would go with the Eheim 1262 if it is under your tank. It is quiet and reliable for insump or external. You can add a second one for redundancy more flow from sump to display but the I think you can get enough flow from the vortec and tunzes.
I've been hearing good things about the Ehiem 1260 and 1262. I might use two pumps.