Bluetooth Propane tank monitor

I really like having an 11-pound tank (vs the one-pound tanks we used on our old teardrop). We use it for both the cookstove and heater, but the question is how to check the level without taking it off and weighing it?

I found a $35 device that sticks on the bottom of the tank with magnets. You can adjust the settings for the height of the tank. There's an app for your phone and here's the readout after ten nights:

Here's the link to it:
https://www.amazon.com/gp/product/B01C5RQJHS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Tony

I found a $35 device that sticks on the bottom of the tank with magnets. You can adjust the settings for the height of the tank. There's an app for your phone and here's the readout after ten nights:

Here's the link to it:
https://www.amazon.com/gp/product/B01C5RQJHS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Tony