John wrote:
I'm not sure what youre asking, if you can restate the question that'd help me
)

I _think_ you might be asking about head loss. There are a couple calculators
on the left hand side navigation bar on reefcentral.com.
~John

Head is calculated on the pressure end of the pump. Question was by
placing @3' od pipe and 2 elboes on the supply end of the pump 2x input
size will this affect pump performance.