Having problems with pressure had aplumber out to fix it he replaced the pressure switch and filled the bladder up to 20psi and now it is down to 10psi this is the 2 time he came out in 3 weeks how can we fix it ourselves there is water in the well it is low but the pipe
Is submerged?

First of all the bladder tank must be charged correctly. 10 and 20 PSI don't get it!
To set the air pressure in a bladder tank, look at the cut-in pressure on your pressure switch. Now drain the line down with the pump off. When there is no more water coming out of the hose bib that you drained the system down with, set the pressure in t6he bladder tank at 2 lbs. below the cut-in pressure. Check it with a tire gage. If your pressure control is set to come on at 20 PSI and go off at 40 PSI then your gage should read 18 PSI. Hope this helps and thank you for rating my reply. If the bladder tank loses pressure perhaps it's faulty and should be replaced. If youreplace the tank don't forget to charge the new tank with the correct PSI. Good luck, Tom

If you are losing air pressure check to see if valve stem is leaking.