I am having a problem with my water pressure. Water tank and switch are ~20 years old. Well pump is about 5years. Problem is the water pressure intermittently drops to zero or near zero.

Yesterday I checked out my system. I adjusted the tank (bladder) air pressure to about 35-38 PSI, and the cut on to about 42 and cut-off to around 62. Everything worked fine for a couple of hours. Then the pressure started getting wonky. Here is a video ( ) of the tank and pump cycling. As you can see and hear, the cut-off/cut-on are about right. Immediately after the cut-on, the pressure suddenly drops to near zero (about 10psi in the video, sometimes to zero.)

Any suggestions? Do I need a new tank or switch? Hopefully, I don't need a new well pump!