I have a situation where I can't seem to find a straight answer. I've tried some engineering websites with no luck. What I'm trying to determine is how much pressure loss with I experience by reducing a 3" pipe down to 2" with a 10hp, 120/gpm submersible well pump. I have a flow meter installed in the 3" pipe but, it's minimum flow range is 3gpm. I need to find a way to detect flow as low as .5gpm. It is being proposed that I reduce the size of my pipe from 3" to 2" to accommodate a lower gpm meter but, I'm concerned about pressure loss, thus my original query regarding pressure drop. I also did some limited research on an ultra-sonic flow meters but, can't seem to find one that is correct for a 3" CPVC, Sched 80 pipe with well water inside it.