Reef Plumbing Experts?

[Myka]

The answer to #2 really depends on how much flow your return pump pushes. Check the manufacturer recommendations (should be in the instruction manual) to make sure that they recommend flow through 3/4". Usually the size of the outlet on the pump is a good sign - if it is a 1" outlet, chances are the manufacturer recommends 1" all the way from the pump to the tank with no restriction. The best bet if you can't find the information in the manual is to email the manufacturer for confirmation - most of them will reply to you within a few days.