Need to know what is the quietest & highest GPH return pump

[Mrfish55]

I had the same problem as you, was getting nasty resonance and driving me crazy, I installed rubber couplings on the intake and returns right where they enter/exit the pump and installed damping pads ( from Sears, intended to go under washing machines) and it made a huge difference to the sound I was having. Changing out your intake to a larger line should make a big difference for you as well, restricting the intake can cause cavitation and vibrations.

[The Grizz]

Changed the inlet today to an 1.5" but still have a little reverberations coming from the pump. Next step is to change the outlet side to an 1.5" tee into 2 - 1" lines with rubber hose but maybe not until next weekend.

[Big Tang]

Just use a six inch piece of spa flex on either side of your pump (intake/outtake )and that should look after any resonance from your pump that's what I do for every reeflo I install.

[The Grizz]

Already have spa flex on the outlet side and have no room for it on the inlet side.

[RuGlu6]

Have you considered water blaster pumps?
Silent and push a lot of water.
2600gph both internal/external
3 year warranty from Coralvue.

http://www.goreef.com/Water-Blaster-Pumps
However i have never had one so no first hand experience.