De,
they have a whole bunch of different little gadgets to tell if you are running low, or not.
They have a few styles that attach directly to the bulk propane outlet:
ONE STYLE
ANOTHER STYLE
AND YET ANOTHER STYLE
And then they have the "El Cheapo" magnetic ones.
HERE'S ONE
HERE'S ANOTHER ONE
AND YET ANOTHER STYLE
Personally, I don't use anything. But I was thinking about one ...maybe.
In Christ: Raymond