Hola Chevytown13!
Let me just ask you this question hermano; How did you get to know that you have 50 cubic feet of gas left in your tank when your cylinder pressure gage will only let you know how many pounds per square inch (gauge) or it's metric equivalent?
Maybe you're reading like Dee mentioned, 50 psig. correct?
You should also have another guage or vertical (clear plastic) tubular meter attached to the regulator, correct?
This is called your flowmeter and what you are reading there is your flow rate in cubic feet per hour which btw, is not the same unit of measurement as is the pressure inside the cylinder so, remember this cardinal!!! Dee explained this pretty good to you also and I would like to add that these variables also change if there is a significant change in relation to how above or below you are with respect to sea-level so, if you're high enough in the mountains or down in Death valley - you'll notice a difference as far as how fast you go through a cylinder of gas hermano...
Hey Caballero! As long as you keep an open mind, you'll always be learning something new everyday just like I and everyone else in this forum does!!!
Que Dios te bendigas!!!
Respectfully,
SSBN727 Run Silent... Run Deep!!!