AlkaSense® - Online Total Alkalinity Monitor

The AlkaSense® from Pi – A Smarter Way to Measure Alkalinity Online

Traditional online methods for measuring total alkalinity generally use one of two methods: titration to a fixed pH (like pH 4.3), or colorimetric analysis using multiple reagents. Both come with their own disadvantages. Titration relies on pH sensors, which often need frequent calibration, cleaning, and replacement—typically lasting only months. Meanwhile, colorimetric systems require constant replenishment of costly reagents and tend to be expensive to purchase and operate.

AlkaSense® changes the game.

Instead of relying on pH or color change, AlkaSense® uses a novel approach—conductivity-based titration—to measure alkalinity. Here's what makes it different:

• No calibration needed – the conductivity method doesn’t rely on absolute conductivity values, just the inflection point.
• Only one low-cost reagent – typically PTSA (Paratoluenesulfonic Acid).
• Plug-and-play simplicity – install it, and you're ready to go.
• Low maintenance – up to 6 months between service intervals.
• Consistently accurate and stable – excellent process control
• Suitable for all potable and process waters

If your system deals with significant solids, AlkaSense® can be paired with an automatic self-cleaning particle strainer for hassle-free operation.

Plus, it’s available as part of Pi’s multi-parameter controllers—so you can integrate measurements like pH, turbidity, and more, all in one system.

With no pH sensor, the AlkaSense® uses a conductivity sensor to indicate when the alkalinity in the sample is used up by the automatic titration of an acid (usually PTSA). As an acid is added, it uses up the alkalinity and changes the conductivity. Once all the alkalinity is gone, by continuing to add acid the conductivity changes but in a different way. As AlkaSense® knows the amount of an acid of known normality that has been added, it can calculate the total alkalinity of the sample using the point of inflection. This clever use of conductivity as a measurement means that the AlkaSense® never needs to be calibrated! Also, because conductivity sensors have no moving parts or sacrificial elements, the AlkaSense® is extremely robust, reliable and long lived. 

In turn, this will enable operators who have previously been restricted to offline alkalinity measurements to measure alkalinity online with the automation that opens up. Examples of this include simming pools, water treatment works, and cooling towers.