I used 1", the smaller the pipe, the more psi you will lose.
I found an online calculator to help me calculate the pressure drop resulting from different pipe sizes. http://www.engineeringtoolbox.com/pr...pes-d_852.html
It seems that it is better to use larger pipe (55ft of pipe).
If I use 1" pipe, the pressure drop is .01psi
If I use 3/4" pipe, the pressure drop is .05psi
If I use 1/2" pipe, the pressure drop is .39psi