Return pump advice

[Matt]

Single overflow, 44g tank, 1 1/2" drain, 3/4" return. Current pump came with the aquagiant setup 13 months ago, (Weipro WH-6000 - nominally 4000lph). It has cracked at the base of the outlet, and is leaking and losing head pressure.

I need to replace it. Suggestions for an appropriate in-sump replacement?

And, got one for sale?