For 32 years, the voice of the pool and spa service professional.

Testing is only true measure of water quality

By Doug Walsh

Pool and spa service professionals are not just people who wield a T-Pole, brush and a 4-pack of chlorine jugs.

Sure, making certain that their pools look great and maintain a sanitizer residual each week are part of the job, but clearing the pool of debris and pouring in some chemicals does not define the true professional.

Customers expect — and, indeed, successful technicians provide — a number of critical services that make them invaluable, including preventing bather illness, providing bather comfort, and protecting the pool structure and equipment from damage.

Just what is the common denominator to make these things happen? The answer is simple yet oh so complicated. They must monitor two important water chemistry parameters: water balance and water sanitation.

The term “monitor” does not mean taking a good look at the pool water. Neither does it mean squirting a little bit of OTO and phenol red into the water and watching for a chemical reaction.

No. The only solution to making a proper analysis of water is to test it, test it on a regular basis, and test it with reliable testing equipment.

That’s because the condition of the water can change at a moment’s notice. One day, it’s sparkling clear. The next day, following gale-force winds, driving rain or a children’s pool party, invisible chemical reactions may begin that could vastly alter the water’s characteristics.

The true professional shows up onsite armed with an accurate and dependable test kit. Aside from taking a water sample to the lab for analysis, it’s simply the only way to determine how much chemical treatment is necessary to restore or maintain water at its best quality.

Testing can accurately determine the proper sanitizer levels to keep bathers safe. It can also measure the three main components of water balance — pH, alkalinity and hardness — that can keep water comfortable for bathers, structure and equipment.

Testing can also determine ideal target ranges for a number of other water parameters that may be important for a particular pool — including metals, phosphates, salts, TDS and cyanuric acid.

Service professionals commonly employ four basic methods of on-site testing:

• Colorimetric — which relies on color matching a water sample treated with a reagent to a comparator test block,  including photometric testing and dip-n-read test strips. This method is used for disinfection and pH testing.

• Titrimetric — which includes using a standard reagent, added by the drop to a water sample. Once an “endpoint” is reached, an indicator chemical is also added by the drop to determine parameters with precise accuracy. This method of testing is used for disinfection, total alkalinity and calcium hardness.

• Turbidimetric — which measures the water clarity as a standard reagent is added to a water sample. This method is commonly used for testing cyanuric acid levels.

• Electronic — which includes handheld electronic test meters that probe for a number of parameters including pH, total dissolved solids, ORP, and nitrates. 

The major parameters included in water balance are pH, total alkalinity, calcium hardness, water temperature and total dissolved solids.

Paid subscribers have full access to all the news affecting the pool and spa service industry. Read the entire issue — and every issue —  by ordering your subscription today online. Become a subscriber by following this link. Or, contact our circulation department at 949-916-0292 or email for details.

Alternatives can provide ‘killer’ back-up plan

Water-neutral pools capture every drop