Bladder Tank Maintenance

I keep forgetting the proper way to chek pressure on my bladder tank...

I have a 40/60 pump switch so...
1. Turn off pump.
2. drain pressure from system.
3. check air pressure on bladder tank and expansion tank.
4. close drain valve and turn on pressure pump

so, for step #3 should the air pressure be 38# or 42#.
this time I'll print this out and attach it to the tank for next year...
Thanks!!!

Short answer, 38 PSI.

Thanks!!! Getting older, can't remember things like I used to...

air

38 psi will leave you with 2# of water when the pump starts. 42 psi you will run out of water 2# before the pump starts.