I have a bladderless 50gal(?) tank and just drain it and fill it again once or
twice a year. The pressure switch sets its own pressure with the
amount of air the tank has in it when it's empty.
(Fast way to drain tank : garden hose, Y connector on tank outlet,
and drill pump. Pump for 30 seconds, and then flip the unattached
Y inlet open to let air in, repeat. Takes about a half hour. Otherwise
it takes 12 hours to drip empty.)
I was always afraid to use the schrader air valve because of putting
oil in the water. At 35 years old now, I doubt the valve works anyway.
Just to suggest you can ignore the bladder entirely.
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