I don't think the Quiet One is going to do it for you, if you are going with this brand, I would go with the 3000 or 4000(4000 being a better choice, better to have too much than too little, IMO). I personally don't like the Quiet Ones, I have two 9000 models that I have had problems with(noise, starting and stopping for no reason, not easily serviced, 3 broken impeller shafts) I like MagDrive's for submersible return pumps, have used them for years and can honestly say have never had any problems with them( I did crack the faceplate on one, but that was my fault for overtightening it, oh and had to replace an impeller in one that was about 6 yrs old) I would go with a Mag 9.5 or 12, when you figure in the head loss, plus pipe friction loss(T's, Elbows, pipe sizing,etc). I would run the largest size pipe from the pump to the tank then split for the two returns right before it goes into the tank, will help a little with friction loss, I would use at least 1" return piping, then reduce to 3/4 when you have to. There are many ways to do this, this is just what I would do for a basic sump set-up for your size tank.
Matt
