Grundfos MQ... stops and starts again with a ... tap | Terry Love Plumbing Advice & Remodel DIY & Professional Forum

I ask you for help and advice in understanding what the problem may be before throwing the pump in the garbage. As you can see in the video it starts then stops and starts again after a shot in the pressure tank.

My idea is to replace the pressure tank but I want to be sure that the problem is there before spend money in a old pump.

Any suggestions will be appreciated

Thanks
Marco