Problem:
Seems like my pump is taking more and more time to fill the pressure tank now. By that I mean that when I used to flush the toilet (for example) the pump would start and run for maybe 1 minute, lately I found that my pump was running longer when I used water, I timed it this morning and after a flush it takes 3 min 36 seconds for the pump to cut out. When I watch the pressure gauge on the pump the cut in happens at 35 psi and the cut out at 55 psi. It takes the pump almost 4 minutes to go from 35 psi to 55 psi. It was way quicker than that before. The pump is 3/4HP Jet Pump with cut-in/cut-out set to 35/55, the pressure tank is a blatter type, the input hose size is 1 1/2" and the ouput hose size is 1". The well is sandpoint well and I think it's like 25 feet or so.

Action Taken:
This morning I took the pump apart suspecting a plugged injector but the injector and impeller looked fine.

I checked the blatter tank and at empty the pressure reads 20psi and at full it reads 45 psi.

I don't get any air bubbles in the taps, the pump won't lose it's prime, watching the pressure gauge on pump it doesn't leak pressure (the gauge stays at 55 until I use the water).

Questions:
Is my well getting dry? How can I check that?
Is my sandpoint clogged? How can I check that?
What tests could I do to isolate the problem?

Any help greatly appreciated!

Serge.