On 15 Aug 2018 11:33:58 GMT, trader_4 wrote:

What were you expecting?

I was expecting 38 psi in the bladder since that's the precharge pressure.
I only got 18 psi.

Funny thing, the pump motor gauge read 55 psi when the bladder read 18 psi.
I will replace that pump motor gauge as soon as I can.

Was water used?
If no water is used, it should have had no pressure drop.

I am embarrassed to admit that the irrigation system has leaks in it, so,
I'm sure water was used overnight.

If you left a faucet open, it should be zero.
The faucets were all closed.
But, the irrigation system has a couple of leaks.

To be clear, I left the power off on purpose so that I could run that test
this morning. So it did what I expected.

The only thing unexpected was that the bladder is 18 psi; not 38 psi but I
probably need to make sure I *isolate* the bladder from the storage tanks
(which can give it a few PSI perhaps?).