I recently (3 weeks ago) added the Sense and Dispense system to my Pro Logic PS-8.
I have tested the water both myself (two different test kits) and taken my water to a local pool company. All of the tests show the water is near perfectly balanced.
However, my ORP sensor is reading 110mV at its lowest, and 190mV at the highest over the last three weeks. Hayward says it should be at 650mV to be correctly balanced. I am starting to suspect the ORP sensor is bad.
They were never dry for more than a 20 seconds during the install. The PH sensor is accurate, its only the ORP that is reading low.