My idea, opinions please

[Nate]

What I'm saying is the pump might have to be overkill to be able to handle the head height. Instead of just throttling it back for the two nanos, as that would put extra load on the pump. Run a third line, a recirc line if you will back into the sump with a ball valve too. Will just help keep the pump working longer.

Also with pex, not traditionally used for aquariums. Will get the same out of flexible PVC. And I gotta ask how the pex will be hooked up to the pump. Will the crimp be submerged. Do crimps rust? What are they made of ?

Is use flex PVC. If you're having trouble finding any pArts let me know I retail them out sometimes through my aquarium maintenance company.