What should I change for diaphragm pressure tank?

[Toepaz]

A little late for this reply. Your $ 7000.00 water problem. You have what is called a water logged pressure tank.
An easy fix. You lost your air cushion above your water. Country living. Been there for over 60 years. Nothing wrong with your system .
Better than any bladder tank s. They are just a problem some where down the road. Bladders always break and the thin steel tanks of today usually rust out. On my flexcon non bladder tank I have a pressure gauge on top with an air valve that I can put air in to create an air over water compression.
Just add air. If starts coming out of your taps bleed some off. This will put you back to having a longer time between pump kick in and out. With an 80 gallon tank you should be able to flush a toilet a couple of times before your pump kicks in. About 50 to 60 gallons would be in the tank and the rest would be air cushion. Let your pressure drop to just before kick in. Add about 20 to 25 LB of air and start from there.
Hopefully this was help full.
Trapper.

 

[Valveman]

Yeah you picked up an old thread. Diaphragm tanks are much better than "non-bladder" tanks. Bladders, diaphragms don't break as long as you limit the number of on/off pump cycles. Cycling makes the diaphragm go up and down until it breaks like bending a wire back and forth over and over. Good that you have learned to keep airing up your old bladderless type tank as that has to be done on a regular basis. Most people don't know the tank is waterlogged and won't take the time to air up the tank every few days or weeks. Diaphragm tanks don't need maintenance and are much better for the average person. With enough air in the tank, an 80 gallon tank only holds about 20 gallons of usable water. Your water doesn't come from the tank, it comes from the pump. All the tank is for is to limit the number of on/off cycles. When you have a Cycle Stop Valve to eliminate the cycling, a small diaphragm tank is all that is needed to get strong constant pressure to the house without all the adding air and maintaining stuff like you have to do with bladderless tanks.