The pH Pages

pH meters, pH measurement, and pH control for aquariums, or whatever your needs may be.

pH Measurement and Control for the Planted Aquarium

Build a simple and inexpensive pH meter. Additional circuitry enables you to control CO2 injection in a planted aquarium to stimulate plant growth.

The Simplest Possible pH Meter

You can build a super-simple pH meter with just a pH probe, an op amp, two batteries, and a voltmeter.

Buying a pH Meter

How to select and buy a pH meter

Calibrating and Caring for a pH Meter

How to calibrate a pH meter.

pH Measurement Components

Components for measuring and controlling pH