Return Pump plumbing Question

[italquam]

I currently have a Ecotech Vectra m1 and it is all plumbed with 3/4 inch lines and manifold for my Algae scrubber.

The New Vectra has 1 inch output, also many other pumps have one inch outlet. Does anyone know if I go from one inch down to 3/4 inch would that affect the performance or anything with the pump ?

 

[Potatohead]

It will still work fine, but the head pressure is increased substantially, slowing the flow rate.