On Aug 20, 8:11*pm, SF Man wrote:
On Fri, 19 Aug 2011 08:18:43 -0500, Pete C. wrote:
one of the simplest ways to monitor for low tank
level on this apparently non pressurized tank would be to install a
decent pressure gauge

The problem is that the holding tank isn't pressurized, but, the piping
goes immediately to an adjacent 4-foot tall blue pressure tank and pump.

So, the water, to the house, is pressurized.

You don't need or want the holding tank to be pressurized.
The weight of the water in the tank creates pressure and
that is what you measure with one transducer. That
pressure tells you the exact level of water in the tank.