A vacuum gauge on the suction line would be interesting. I expect the suction/vacuum is increasing as the flow decreases. If that is the case, then you cannot blame the pump.
the impeller is threaded on to the motor shaft. After thousands of cycles the threads could be warn down. Threads do always stay tight. As the motor shaft get hot the impeller threads cold be expanding causing slippage.
The impellers are like a disk with the blades inside if it. Usually plastic. When pumping you do pick up sand and millions of gallons going through wear them down. As stated before, more suction is needed and it cannot perform.
A vacuum gauge on the suction line would be interesting. I expect the suction/vacuum is increasing as the flow decreases. If that is the case, then you cannot blame the pump.
I suspect the water level in the points drops. That can be because the screens are crudded up. But it could be something else that causes your pipes to replenish more slowly than the neighbors.
I suspect the water level in the points drops. That can be because the screens are crudded up. But it could be something else that causes your pipes to replenish more slowly than the neighbors.
