My tank pressure cycles rapidly from 30-60 psi when I turn my water on. This just started. I have a new submersible pump and water line that is 2 months old. Pressure at the air valve on top of the tank is 24 psi. what could my problem be?

That is typical of a waterlogged tank. When the tank is at 60 with no water being used, depress the Schrader valve center pin. What comes out? Water? If so, you have a leaking bladder.

If you install a new tank, and you likely will, set the tank pressure to 2 psi BELOW the cut in pressure before you install it. So, for instance, if your system comes on at 40 psi, then you would set the tank pressure to 38 psi.