[jimcol]

I don't have a monitor on mine. I only turn on one bottle at a time that way I know when one is empty. (If camping when the furnace is required I'll turn on the second bottle in the evening so I'm not outside in the cold and dark, in the middle of the night, turning on the other bottle when the first goes empty. Come morning I turn it back off.)It's rare I ever have a tank go completely empty. After years of RV'ing you get pretty accustom to what your usage is. Either by lifting or sound I know when one is getting close. It's then I put the full one on line and have the low one filled.