I did find a 37 Gal. tank. It comes in a kit, has every thing you need at
http://www.justgastanks.com but it is $599.99 to pricy for me. The dimensions for the origanl tank is 29"x14"x17" 21 gal. The 25 gal. out of the 73- is 28"x28"x11" and the 31 gal. is 28"x28"x13". Will the sending unit out of the origanl tank work in the 31 gal. tank?