Photometric Pool Water Testing Explained
As pool water management becomes more advanced, traditional testing methods are being replaced by more accurate technologies.
Probe based systems designed to control chlorine and pH levels have been around for many years but innovators, like POOL LAB, have developed and patented ASP technology.
The POOL LAB ASP – Auto Sampling Photometer obtains samples of Pool or Spa water directly from the filtration plumbing circuit, mixes reagents with the sample and completes the photometric analysis.
Photometric determination of free chlorine and pH levels in Pools and Spas is known universally as the gold standard technology.
One of the most reliable methods available today is photometric pool water testing.
What is Photometric Pool Water Testing?
Photometric pool water analysis is a highly accurate, digital testing method that measures light absorbance through a water sample mixed with chemical reagents. It converts color intensity into precise digital readings for parameters like chlorine and pH, offering faster, more reliable, and objective results compared to visual, color-matching test kits.
How Photometric Testing Works
- A water sample is collected – POOL LAB ASP completes this automatically
- A reagent tablet is added – POOL LAB ASP uses stabilised liquid reagents
- The sample changes colour – POOL LAB ASP mixes the reagents in the patented chamber
- The device measures light absorption – POOL LAB ASP uses specific wavelengths of light
- Results are displayed digitally – POOL LAB Chlorinator displays the results and stores them
Benefits of Photometric Pool Testing
- High accuracy and repeatability
- No calibration of probes required
- No probes to clean and maintain
- Unlike an ORP probe that provides a loose approximation of the free chlorine level, the Photometric result is in universally understood parts per million, ppm.
- Digital, easy-to-read results
- Ideal for commercial pool compliance
- POOL LAB ASP has an industry leading 5 year warranty* compared to most probe systems with 1 year.
Photometric Testing vs Traditional Methods
Test Strips:
- Quick but unreliable
Liquid Test Kits:
- More accurate but subjective
Probe Systems:
- Continuous monitoring but prone to drift
- Require regular manual cleaning and calibration
Photometric Testing:
- Accurate, stable, and consistent
- Does not require the maintenance probe systems require
- Only requires replacement of the reagent sets every 6 to 8 months for a standard pool
Why Photometric Testing is Growing in Australia
Commercial pool operators are increasingly adopting POOL LAB’s photometric systems due to:
- Stricter compliance requirements
- Need for reliable data
- Reduced maintenance compared to probes
- Unlike probes, POOL LAB ASP does not suffer from hydrogen gas interference which is especially prevalent in Spas
Residential Pool builders and service companies are also adopting POOL LAB’s photometric systems due to
- More reliable than probes
- More accurate results than probes
- No cleaning or maintenance related to probes
- No calibration required
- Industry leading 5-year warranty* compared to probe systems that typically have a 1-year warranty
- More economical over time
Is Photometric Testing Right for You?
Photometric testing is ideal for:
- Commercial Pools and Spas
- Residential Pools and Spas
- Aquatic centres
- Facilities requiring accurate reporting
Learn more about how it compares: Pool Lab vs Probe-Based Systems