Changing tank to switch line on bore well tank

Hi all.

I have a 1975 bore well with a pressure tank right at the top. I believe that I have a issue with the water line from the tank to the switch, because I can have a full tank with pump running, but the gauge will not reflect this (will at times read 0 even though we clearly have pressure). I've confirmed to the best of my ability it is not the gauge, switch, tank, or pump. So I believe I've got crud/sediment in the water line from the bottom of my tank to the switch that is preventing a good reading.

My question is, how does one remove the tank and access the connection at the bottom? Once empty, does a tank like this typically just pull out? Does it unscrew? Any advice would be appreciated.

If all of this is from 1975, every part is ready for the rest home. I would budget for all new parts.

Pressure Guages are cheap! Replace the pressure guage and then if you don't get an accurate reading, get back to us.