I have a shallow well (12 ft) with a GE 1/3 hp shallow well pump hooked to a 42 gallon epoxy lined (bladderless I think) water tank. It gets full of water and I have to almost completely drain it and then refill it frequently or else the pump comes on with any demand for water. What kind on AVC do I need and how do I hook it up? My tank has the inlet on the bottom, half way up is an old inoperative AVC, above that is a Schrader valve and on the top of the tank is a plug. I see Granger makes an AVC with a float on it but I don't know where to put it on the tank or how to hook it to the pump. Also should I put a gauge somewhere on the tank? There's an old rusty gauge in the line before the tank and it reads 25lbs. Any help on this matter would be appreciated. Thanks.