My last tip I have for the group is to modify a brass fluidmaster float valve to accept a copper sweat coupling. I was surprise to find nothing fits the bottom of auto fill tanks that use fluidmaster valves. You can get a brass Fluidmaster here......
http://www.plumbingsupply.com/fluidmaster-pro-series.html
http://www.pentairpool.com/misc/owners_manuals/skimmers/T40F_Autofiller.pdf

I used a hacksaw and a hammer to remove the plastic from the brass threaded bottom. Next I used my angle grinder to remove one end of the threads and a little more so a copper coupling will slide on. Using my plumbers torch I sweat on the coupling, a length of 3/4" copper, and a hose bib at the end. It makes adding a gage and gas quick and easy. Water is already hooked up at the other end.

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Hap