Clunking noise water pressure tank

[cat novak]

Because of a recurring noise coming from water pressure tank and lack of pressure, I had the water tank replaced two weeks ago (the old one was changed in 1992). It solved the problems.
I'm currently up in the middle of the night because that noise was back again: something goes of for 30-45 seconds and then stops with an clunk and does it again. It did it four or five times and seems to be over.
Is it supposed to do that once in a while and I just don't notice, it just happened that it woke me up?
Sorry for the lack of technical precision.

 

[Valveman]

The clunk is probably water hammer from a check valve when the pump starts or stops. You need to watch the pressure gauge and see if it is happening on pump start or stop. I don't think the tank has anything to do with the noise.