What size pressure tank?

[Martin_Meyers]

The tank on my mothers well is water logged. It's 40 years old, so time for a new one. The existing tank is (I think) about 80 gallon size, not sure how much water it holds. But the well water is only used for irrigation, she also has 2500 gallon non-pressure tanks that feed the pressure tank. The water doesn't go into the house, it's not potable. Does she still need an 80 gallon tank? Is a smaller and less expensive tank better justified?

 

[Valveman]

An 80 gallon pressure tank only holds 20 gallons of water. Your water comes from the pump, storage tank, well, but not the pressure tank. The only reason for a pressure tank is to limit the times a pump cycles on and off to supply the water you need. If you have a Cycle Stop Valve to limit the cycling, you only need a 4.5 gallon size tank. The PK1A kit with the CSV1A Cycle Stop Valve and 4.5 gallon size tank will replace a big pressure tank and do a much better job.

See it here. https://cyclestopvalves.com/pages/pk1a-pside-kick