Live in a thirty to 40 year old house with a well. The water pump is a Water Ace R100 deep well pump. The pump appears to be running ok but there is a volume problem. If you open two faucets up at once, the water slows to a trickle. The pressure is set to cut in at 30 and out at 50. The precharge in the holding tank 20-30 psi. Pressure at the gage at the tank reads upto 50 psi with the pump running. I tried to adjust the cut in and out, it would only increase the pressure to 54 psi and the pump would not cut out(it ran for 6 hours) Any ideas, short of replacing the whole system?