I would like to change from a jet pump to a submersible. I dug down and found the top of the well casing. It looks to be 4 or 5 inches across. For reference, I'll say the 2 pipes from the house come in at about 6 o'clock. There is a 1/2" or so breather pipe going straight up at about 12 o'clock. There is a bolt head on either side of the breather and one at about 7 o'clock to the left of the water pipe hook up. There are 2 slots in the top. This is as far as I have gone and would appreciate some help on identifying what I have and what possibly to expect. I replaced the pump about 6 years ago. The old pump was leaking and the tank did not have a bladder.