I have searched online and on this forum but cannot find the answer to my question. I would like to self install a Pentair Intellichlor IC40 this spring but my piping may be a little tight. Everywhere I look the measurement states 17 inches but where is the measurement taken from? If each end allows for "seating" of PVC pipe of 3/4 to 1 inch is the needed spacing really something like 15 inches? My piping run is tight and I don't want to do a lot of rerouting if I do not have to. Thanks for anyone's help.