closed loop pump?
 

I am looking to set up a closed loop on a new 120gal... probably have two 1" outlets... thinking of a 1.5" input... want to go in the 2000gph range.

What pump would you buy?

Hmm, the only pumps that I can think of around that range is an Ampmaster 2700 or a Mag 18. Everything else is smaller or larger...

I'm running an Ampmaster 2100 through an OM 4 way for my closed loop. I have a 2" inlet, but a 1 1/2" would be fine for that pump. I have four 1" returns from the OM. It has a maximum output of 2880 gph at zero head. At approximatley 6' of head it will have the 2000 gph that you want.