I'm hoping someone can point me in the right direction.
We have a new cottage, just completed last year with a drilled well (213 ft deep), submersible pump (about 70 feet down, water is at 13 feet) and a Red Lion RL20 (20 gallon) pressure tank with a Pumptrol pressure switch.

The tank and switch had been hooked up for 3 years to our RV while we were building. The tank sat outside during this time and endured summer heat and sub-zero winters (empty of course).

Once the cottage was complete, we brought the same system inside and plumbed it the same. It feeds 1/2" copper piping to a kitchen sink, toilet, shower, bathroom sink and 1 outside spigot.

A couple of weeks ago, the pressure and flow were okay. I decided to check the bladder pressure just to be sure everything was okay. The pressure was down to 8lbs, so I added air until it reached 28psi, as specified by Red Lion. The cut-in pressure is 30psi and the cut-off is 50psi.

There is no pressure loss when everything is static.

However, this week we were up at the cottage and noticed very little pressure and flow, yet pump runs very little and pressurizes very quickly when needed.

We have no in-line filters and even the outside spigot seems to have reduced flow and pressure.

Could the pressure tank be the problem? Is it time for a new one?