[NanoReefWanabe]

Originally posted by nodbugger
High speed, low drag. Low speed, high drag.

A sudden expansion in pipe sizes will decrease the flow and it will suffer from head loss because the water has to slow down, which also increases the pressure.



http://www.efm.leeds.ac.uk/CIVE/CIVE...pe%20flow2.pdf

i would tend to agree with this too..larger pipes are going to have more water in them....more water is going to weigh more...and move slower...both are going to increase head pressure...i dont need to be an engineer to know that i can blow water up a straw a good 5 feet or so...but you can bet your butt i cant blow any amount of water up a garden hose 5 feet...and my lung capacity is going to be the same in either setup...LOL