OK, I found a steal for a 210 locally and am going to upgrade from a 150.

Currently I am running a closed loop with 2 Hydor K4's inside the tank and the closed loop run by a Little Giant 4-MDQX-SC. Not sure what my gallons per hour are running through the system based upon my plumbing but it seems like it may be at the max so am figuring I need to upgrade my return pump to go to the 210 gallon.

Anyone have any good quality recommendations and something that will be QUIET :-) as well as improve flow????

Also, would a 3rd or 4th Hydor K4 be a good idea? No SPS, just softies, caps, Monti's etc...

Little Giant specs:
4-MDQX-SC 17.0 ft 1225 1080 675 1" 1" 145