Science

Simple sensor designed to continuously analyze pool water

Simple sensor designed to cont...
The device could work on its own without human intervention, for up to three months
The device could work on its own without human intervention, for up to three months
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The device could work on its own without human intervention, for up to three months
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The device could work on its own without human intervention, for up to three months
The chlorine/pH sensor, pictured here while still in development
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The chlorine/pH sensor, pictured here while still in development

It's important to maintain proper chlorine levels in a pool, as too much can cause skin and eye irritation, and too little won't kill bacteria or other microbes. A new device could help, by cheaply and automatically checking a pool's pH and chlorine content.

Currently, most pool owners must periodically use testing kits to manually check the water. The process is prone to human error, however, plus owners may forget to perform the tests, or simply not bother.

There are also sensor-equipped systems that analyze the water on an ongoing basis – according to scientists at the University of South Australia, though, these setups tend to be complex and expensive. With that in mind, those researchers are developing a simple, low-cost microfluidic sensor that could do the job.

Permanently installed at the side of a pool, the "credit card-sized" device routinely draws a small amount of water into tiny channels that are embedded in its glass body. That water then mixes with two reagent chemicals by the names of methyl orange and phenol red.

An integrated photometric sensor subsequently measures how much the methyl orange has been bleached – indicating the water's chlorine level – and the extent to which the color of the phenol red has changed, indicating the pH. Those readings could then be wirelessly transmitted to the user.

What's more, a single fill of the two reagents should reportedly be good for three months of use.

The chlorine/pH sensor, pictured here while still in development
The chlorine/pH sensor, pictured here while still in development

A prototype has already been tested on water samples from 12 swimming pools (nine domestic, two public and one outdoor public), which were drawn on multiple occasions. The readings "compared favorably" with those obtained using a variety of traditional methods.

"The chip quickly and continuously does all the work of a chemistry laboratory using tiny amounts of chemical, without leaving the poolside," says the lead scientist, Assoc. Prof. Craig Priest. "For pool owners, this removes the arduous task of manually testing swimming pools and avoids overuse of pool chemicals, which saves time, money and, most importantly, the risk of infection from incorrect pool chemistry."

The technology is now being commercialized in partnership with electronics company Tekelek Australia, and may be on the market soon.

A paper on the research was published this week in the journal Sensors.

Source: University of South Australia

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If it can text the user it can text a chlorine dispensing unit to make it automatic.