Propane tank

Personally I have never found a guage to be accurate. I tun twin tanks with MANUAL switch over so I know when to fill a tank and am not surprised when both tanks run out.

Are we discussing Propane Portable CYLINDERS for Trailers (DOT Jurisdiction)
OR
Propane Fixed TANK for Motorhomes (ASME Jurisdiction)

Tanks ....typically have gauge on tank and can have remote sender to inside panel

Cylinders ... there are 'gauges' that connect between OPD Valve and Pigtail (limited info cause they indicate pressure)
There are heat sensitive tape you stick to outside wall of cylinder
There are weight sensors that you place under the cylinder and then they transmit weight to receiver/app on phone etc

And then one can just lift the cylinder to guesstimate how much is left
OR use a auto swap reg (if you have 2 cylinders) ....1st one runs out RED Indicator shows (flip indicator level...GREEN shows) remove empty cylinder and get it refilled
*REPEAT as necessary

JimK-NY wrote:
Lift the tank and judge the weight. That will give you a pretty good idea of how much is left.

Try that with a 40# tank.

Boomerweps wrote:
There are stick on gauges that react to liquid temp differential in the tank so you can have an idea of the tank level.

Are those the kind where you have to our warm water over them?

There are stick on gauges that react to liquid temp differential in the tank so you can have an idea of the tank level.

Diamond c wrote:
I’ve always wanted to know how your supposed to know how much propane is in your tank before it runs out?

Don't open both tanks simultaneously.

When one runs out, switch to the other and be on the lookout to get the first refilled.

Lift the tank and judge the weight. That will give you a pretty good idea of how much is left.

"when the first tank empties then the gauge shows red." .

I think this is point, You have a gauge, sounds like the OP does not. Wanting to know how much LP is left requires a gauge.

Diamond c wrote:
I’ve always wanted to know how your supposed to know how much propane is in your tank before it runs out?

Personally I have two tanks and an automatic switch over regulator, when the first tank empties then the gauge shows red. I switch which is primary tank and fill the empty and go on with life.

With an LP tank gauge. If you don't have one on your monitor panel, you can install one at the tank. $10-20 on Amazon.