Okay, so I installed the IntelliPH, very simple, except for the step to drill the 1/2" hole in the 2" PVC pipe you have to be very careful. I learned the hard way by using a long 1/2" bit designed for wood. I thought I was being careful, but maybe just a tiny pressure and snap, it chipped out, disaster! Disaster because there is only enough room (about 3/16" each side between the union and coupler) to attach the inlet. I was lucky to be able to glue in the chipped out chunk without having to redo the entire thing from the heater to the Intellicholor (it was nothing but 90's 45's and couplers).
But here's the tip: Start drilling normally lightly enough to get a divot. Then reverse the drill and with light pressure let it melt and scrape to drill the hole. Once through you can drill forward again while the bit is in the hole to clear it out (clearly not touching the bottom of the inside of the pipe).