I have a Sta Rite MSE-7 pump which supplies water to a 40 gallon galvanized bladderless tank. The tank currently has a Brady AV-42 air volume control valve which is worn and in need of replacement. Is this the correct one for this tank? Would I be better off using an AV-80 or AV-100 valve? I currently have to charge the tank with air from a compressor about once per year to have a 5 to 6 gallon drawdown on the tank per pump cycle. The pump and tank operate between 40 and 60 psi.

Thanks for your help.