If the tanks are over a certain age, they require an inspection (you usually have to pay for this) at a qualified propane tank service center. Take one by the local propane store to have the service date verified before time and spending money polishing the tanks.
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell
2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Tuson TPMS, disc brakes, 16" tires & wheels