Thud/hammer at Tank

Greetings,
Went out a town below freezing so,
Shut off water to house after tank, a welltroll 202,shut off power to pump.All in the cellar.
Returned home turned on water then power to pump.....tank made a banging noise after energizing pump.It now does that every time the p[ump cycles.

Any thoughts

It is probably the bladder hitting bottom. It means your tank pressure is too high. It should be two pounds less than the turn on pressure of the pump.

bob...