How important is the Reynold's number? I'm running 7.5 gpm thru 4 ground loops of 3/4” HDPE (ethanol for anti freeze). Which means my Reynold's number is relatively low (I haven't done all the calcs). According to what I've read, normally would want more like 10-12 gpm for 4 loops to get to optimum number. However, I've got nearly 90 gal in my loop. That means HP will run on low stage for 12 minutes before heat transfer during flow is important. Now I would assume that under constant run times, it becomes more important to get that optimum turbulent flow. Currently my system is not running long enough to do a lot of testing to prove one way or another. My gut feeling is that the difference will be hard to quantify. Maybe someone has an idea on how I could test this?