I found the exact POT that is called for in the blog. It is on this web site http://www.smcelectronics.com/pot.htm and is the eleventh one down on the page. I ordered two today at $4.50. I thought it was allot better than a thirty dollar sender, plus shipping and I get a reserve POT and in the tank. I'm assuming the darker terminal in the middle is for the ground, is this correct?