Ulook: You say you are getting good stratification.
.
It's not really practical to run water on them.
The grill-size tanks, often called cylinders, would usually be bought full.
Without a regulator, the pressure of the propane coming out of the tank will be so strong that it would seem like you just lit a flame thrower instead of a grill.
The ground where your tank will go should have gravel, cement or a firm ground base.