Water Chemistry Controllers

The controller is the brain of an automated pool. It continuously reads your water through pH and ORP probes, compares those readings to your setpoints and switches the chemical feed pumps on and off to hold the target. Everything else on the pad is an accessory to this decision.

Choosing a controller

• pH and ORP controllers cover the two measurements that matter most on nearly every pool. ORP is a proxy for sanitiser effectiveness, and pH governs how well that sanitiser actually works.
• pH, dual ORP and free chlorine PPM controllers add a direct amperometric free chlorine reading in parts per million. That matters where health code requires a PPM value rather than an ORP millivolt reading, and on pools where high cyanuric acid makes ORP alone unreliable.

Why pH control comes first

Chlorine effectiveness collapses as pH rises. At 7.2 a large share of your free chlorine is in the active hypochlorous acid form, and by 8.0 most of it is not. A pool running high pH can show adequate chlorine on a test strip and still fail to sanitise properly. Holding pH in band is usually the single highest impact change you can make, and it reduces chlorine consumption at the same time.

What else you need

A controller needs a flow cell with pH and ORP probes plumbed into a sample line, a flow switch so it will not dose without circulation, and one feed pump per chemical. Probes are consumable and should be calibrated regularly and replaced on a schedule. Salt pools should specify a gold tip ORP probe, which resists the fouling that shortens standard probe life in high salinity water.