Regular pH electrodes like 201T-F, 201T-S, or the glass bulb probes in most pocket testers are only suitable for testing general water solutions — medium to high ion concentration, non-protein solution, non-strong acid or alkali, at moderate temperature — of which common applications are in hydroponics, pools and spas, aquaculture, environmental monitoring, water treatment, cooling towers, education, etc.

For testing pH of special samples such as viscous (sticky), strong acidic or alkaline solutions, solutions at high or low temperature (>50˚C or <10˚C), solid samples, turbid solutions, low ion-concentration solutions & etc…specialized pH electrodes are necessary in order to achieve reliable results. Regular pH electrodes in these special applications usually would generate inaccurate and unstable measurements, and may be damaged by the samples, or even be non-applicable for testing at all.

The Apera LabSen® series professional pH electrodes have over 24 models, among which every model is designed for specific applications and occasions. In the filter on the right side of the page, search by application, and you will be able to find the most appropriate pH electrode for your specific need in the LabSen® Series. If you don’t see your specific application, feel free to call us at 1 (614) 285-3080 or email us at Our representatives will be happy to help you find the most suitable option.