Description

The Rola-Chem 550135 is the heavy duty pH probe with an 8 ft lead, for Rola-Chem digital and analog controller systems.

What it does

A chemical controller decides when to feed acid based entirely on what the pH probe tells it. That makes the probe the accuracy limit for the whole system. When one ages past the point where cleaning and calibration bring it back, the controller keeps dosing confidently on numbers that are no longer true.

Before you order

This is the pH probe, not the ORP probe, and the ORP version is a separate part. The lead is eight feet, so check the run from your probe location back to the controller.