New pump and plumbing

[Humpty]

So i have a 180g tank with what I believe is 2-1.5" overflows and 2 - 1" bulk heads for return lines. I have a queitone 6000 that is on its way out and I was looking at replacing it with a Jebao DCS 9000. Jebao says it does 2300gph and has a native 1.5" connection. My return line is plumbed in 3/4" line. Im assuming I should redo the return line plumbing to all be 1". Is 1" line going to be enough to run this pump properly? If the bulkhead is 1",is there really any use in doing bigger line before the bulkhead? Will a pump with that kind of flow work with 3/4" line?