I've been a do-it-yourself kind of guy for home repairs for over 30 years. Two days a go I replaced a leaky pressure tank. The removal and installation went as expected, but I have an issue I can't figure out. The well pump kicks on much more frequently to keep the tank pressurized than before when water is being used, maybe 3 or 4 times per minute. When I watch the pressure gauge while water is running, there is a sudden drop in pressure shortly after the tank hits its high set point after the well pump kicks off, which makes the well pump kick back on. Even more strange is that when no water is running in the house the system continues to cycle as pressure is not maintained. There is no apparent leak anywhere in the house. It makes me wonder if there is a leak somewhere outside the house or water is flowing back into the well?

Help!

What kind of pump, submersible or above ground.
Did previous tank have a check valve on the well line?