Update, when I start to lose pressure from the fountain, my filter reads 33psi.

Also the motor filter basket is not completely filled with water. There is an air gap. Maybe an inch. So I can see air in the motor basket but this does not happen for maybe 6hrs of the motor running.

So if I turn off the pump, wait maybe 5min and turn back on, we are back to 20psi and the fountain has pressure.