My wife said she recently seen an article on TOH that outlined a propane tank gauge. Does anyone know where I can obtain that information?
I see strip-style tape gauges used on RV tanks but I don't know how well they work. My last above-ground home-type tank had a gauge on it which was reliable if you tapped on it, but not too exact. It was enough to let you know it was time for a refill. Dunno if in-ground tanks have that or not.
Since propane pressure changes with volume and temperature, you won't find one that's accurate. The stick on gauge measures temperature between the cooler tank and the warmer gas. The problem with this style gauge is that you have to be using propane fairly significantly at time of reading for it to register. The most accurate gauge will be one that goes by weight, as you use the gas, the tank gets lighter. There are a few of this type out there, can't recommend a particular one. In lieu of a gauge on BBQ sized tanks, just pick it up and give it a shake. You will not only feel the weight of the gas, you should hear it sloshing. If you don't feel either of these things, it's time to get the tank filled.
I have a gauge attached to the tank, but like was said, it's not very accurate.
Nowadays the tank exchangers give you 15 lbs of gas, so if you know what an empty tank weighs approximately, then you can figure out how much gas you have left.
But this is what experienced BBQers are doing: they buy an additional tank so that they never run out of gas in the middle of BBQing.
In the tank, most of the propane is in a liquid state, under a lot of pressure. The gauge is the same type that is built into the gas cap of a riding lawn mower. They are close enough.
I recently changed propane suppliers and on my list of must have was a remote gauge on a 120LB tank. The gauge in the tank has a small rubber hatch over a connector. I removed the rubber piece and plugged in the remote. It is powered by an AAA battery and is attached in the house near the exterior tank. When you push the button on it the LED's blink and then come to rest at a reading. I check the tank each week and the remote is accurate enough to allow time for a fill order to be placed.
These remote devices work on the Hall effect which is a varying magnetic field based on the tank gauge reading. This is what my remote looks like and it was free from my supplier: http://www.amazon.com/gp/product/B00HS8CZOG/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
I have seen wireless devices for 20LB tanks that RV folks use. These are a somewhat different animal however.
Hope that helps.