Plumbing... Need help

[Fishward]

Originally Posted by shrimpchips

Unless it calls for 1" pipe, you should probably leave it at 1/2" - if you take it up to 1", then your headloss is going to be even greater as there's much more water that the pump has to push up against, so you will get less flow.

+1. i wouldn't change the diam. of your pump output. bigger pipes are only really beneficial for drains.