Adding air to a well tank - HOW MUCH?

The cycling indicates the tank is almost waterlogged. There's almost surely a small leak in the bladder. Best you can do is to drain it completely and start over again. If it isn't too big a leak and there isn't too much water on the bubble side, it'll function ok again for a while, but a new tank is in your (relatively near) future in all likelihood.

It should be 2 lb below when empty.

Fix it quick. Your pump is in the process of being destroyed. Short cycling is extremely hard on pumps.

Adding more air to the tank will be a temporary fix that will have to be done every few months. A new bladder tank is not a budget buster and installation is simple if you are comforatable with plumbing and wiring.

Harry K

Harry K wrote: ...

Good point--

One thing you can try if you can do w/o water for several hours -- when you drain the water side, pressurize the bladder side to several pounds over setpoint value -- say +5 and let sit w/. You may be able to force some of the water back across the barrier but you don't want to put a whole lot of extra pressure on it. This works far better w/ a diaphragm design (which I have) rather than a bladder, but it may still help some.

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I didn't see it mentioned and just in case:

Proper way to add air. Turn off power to pump, drain tank, add air, turn power back on.

You may have a 'low pressure cut-off' circuity in the pressure switch, if so, you have to hold in a button, or a switch that is on the pressure switch until the pressure builds past the 'cut-in' point when you turn the power back on. Haryr K