John Wojtowicz, The Chemist Who Gave Us Modern Pool Science

If you’ve ever used a pool calculator that adjusts for Cyanuric AcidCyanuric AcidAlso called stabilizer or conditioner. Protects chlorine from being destroyed by sunlight. Essential for outdoor pools, but too much reduces chlorine’s killing power., you’ve benefited from John Wojtowicz’s work. If your app corrects Total AlkalinityTotal AlkalinityA measure of your water’s ability to resist pH changes. Think of it as a buffer that keeps your pH stable. Measured in ppm. readings to account for stabilizer, that’s his formula. If anyone has ever explained to you why the pool industry’s Saturation IndexSaturation IndexA calculation that predicts whether your water will deposit scale or dissolve calcium from surfaces. Balanced water has an index near zero. needed updating, they were channeling research he published in the late 1990s.

Most pool owners have never heard his name. The science they rely on every day traces back to papers he wrote after retiring from a 32-year career in industrial chemistry.

John A. Wojtowicz was born in Niagara Falls, New York on October 12, 1926. When he was ten, during the worst years of the Great Depression, he spent several years in an orphanage before going to live with his aunt and uncle. He graduated from Trott Vocational High School in 1945, then earned a B.S. in Chemistry from the University of Buffalo and an M.A. from Niagara University.

He worked for eleven years as a laboratory technician at DuPont in Niagara Falls. After two years in the Army, he joined Olin Corporation as a Research Chemist. In 1959, Olin transferred him to their research laboratory in New Haven, Connecticut, where he worked as Senior Research Chemist until his retirement in 1991.

His career at Olin produced 56 U.S. patents and numerous foreign patents. He authored fifty journal articles and wrote six chapters for the Kirk-Othmer Encyclopedia of Chemical Technology, the standard reference work for industrial chemistry. His encyclopedia entries covered Hypochlorous AcidHypochlorous AcidThe active, germ-killing form of chlorine in your pool. Lower pH means more of your chlorine is in this effective form., hypochlorites, ChloraminesChloraminesCompounds formed when chlorine reacts with nitrogen from sweat, urine, and other contaminants. Causes the harsh ‘pool smell’ and eye irritation., bromamines, and cyanuric acid. He presented papers at national meetings of the American Chemical Society. He was, by any measure, a serious industrial chemist working at the highest levels of his field.

Then he retired. And he turned his attention to swimming pools.

The Problem He Saw

The swimming pool industry had been using the Langelier Saturation Index (LSI)Langelier Saturation IndexA formula that predicts whether your water will deposit scale or corrode surfaces. Zero is balanced; positive means scale-forming; negative means corrosive. since the early 1960s to predict whether water would scale or corrode. The LSI originated in the 1930s with Dr. Wilfred Langelier, a sanitary engineering professor at UC Berkeley who developed it for municipal water systems. His concern was pipe corrosion in closed-loop industrial applications.

The pool industry adopted his index and adapted it. The adaptation involved simplification. Tables of factors replaced the underlying thermodynamic calculations, and approximations accumulated. By the time Wojtowicz examined the formula the industry was using, it had drifted considerably from the original science.

He found several problems. The temperature factors in published tables had been miscalculated and then copied into every major pool operation textbook. The formula used a constant for total dissolved solidsTDSTotal Dissolved Solids. Everything dissolved in your water, including minerals, chemicals, and salts. High TDS can make water feel ‘heavy’ and reduce chemical effectiveness. that assumed 500 ppmppmThe standard unit for measuring chemical concentrations in pool water. 1 ppm equals about 1 drop in 13 gallons., which made it unreliable for saltwater pools. Most significantly, it treated total alkalinity as if it were the same as Carbonate AlkalinityCarbonate AlkalinityThe portion of total alkalinity that actually affects water balance. In stabilized pools, subtract about a third of your CYA from total alkalinity to get this number..

In pools using cyanuric acid (CYACYAShort for Cyanuric Acid. Also called stabilizer or conditioner. Protects chlorine from UV breakdown in outdoor pools.) as a StabilizerStabilizerAnother name for cyanuric acid (CYA). Protects chlorine from being destroyed by sunlight. Sometimes called conditioner., this last issue mattered enormously. Cyanuric acid ionizes in water to form CyanurateCyanurateThe form cyanuric acid takes when dissolved in water. It binds to chlorine, protecting it from sunlight but slowing its sanitizing speed., which is alkaline. When you measure total alkalinity with a standard test kit, you’re measuring both carbonate alkalinity and cyanurate alkalinity combined. The saturation index cares only about carbonate alkalinity, because that’s what determines calcium carbonate solubility. Using the wrong number means your index calculation is wrong, sometimes significantly so.

Wojtowicz worked out the correction. At typical pool pH, roughly one-third of your cyanuric acid concentration should be subtracted from your total alkalinity reading to get carbonate alkalinity. At pH 7.4 with 100 ppm CYA, a total alkalinity reading of 100 ppm actually represents a carbonate alkalinity of about 69 ppm. The difference matters. Water that looks balanced on paper might actually be corrosive.

The Papers

Between 1995 and the early 2000s, Wojtowicz published extensively in the Journal of the Swimming Pool and Spa Industry. His output was remarkable for someone in retirement. A nine-part series on swimming pool water balance rebuilt the saturation index from first principles. He documented the cyanurate alkalinity correction with laboratory experiments and field tests. He wrote about buffer chemistry, calcium carbonate precipitation potential, carbon dioxide loss, and the thermodynamic basis underlying all of it.

The papers are dense. They contain derivations, equilibrium constants, ionization fractions, and activity coefficients. They cite Plummer and Busenberg’s 1982 work on calcite solubility, O’Brien’s 1972 Harvard thesis on chlorinated isocyanurates, and the primary literature going back decades. This was peer-reviewed science applied to an industry that had been running on rules of thumb.

He also wrote practical papers. Surveys of sanitizers and sanitation systems. Product information summaries. Chemical adjustment dosing guides. Safe storage and shipping temperatures for pool chemicals. The theoretical work supported practical application.

His paper on the applicability of the Langelier Saturation Index to swimming pools directly addressed whether an index designed for closed pipes even made sense for open bodies of water. Some argued it didn’t. Dr. Thomas, Langelier’s successor at UC Berkeley, had been quoted saying the index “has no significance to open bodies of water.” Wojtowicz showed experimentally that a properly calculated saturation index was indeed applicable to pools, provided you used the correct formula with appropriate corrections.

Why This Matters Now

Every serious pool chemistry resource today cites Wojtowicz. Industry trade associations reference his revised saturation index equation. Test kit manufacturers acknowledge his contributions to understanding pool water chemistry. His papers are the foundation that modern pool science rests upon.

When you use a modern pool app that gives you a CSICSIShort for Calcite Saturation Index. A more precise saturation index than LSI, based on actual calcium carbonate thermochemistry. or corrected LSI, the underlying science traces to his publications. When someone explains that cyanuric acid affects your alkalinity reading, they’re passing along his research. When a forum post debunks outdated pool store advice using actual chemistry, the chemistry often comes from his work.

PoolFu’s Chemistry Engine

PoolFu’s chemistry engine is built on Wojtowicz’s foundational research. His corrected saturation index equation, his work on carbonate alkalinity adjustment for cyanuric acid, and his temperature-dependent calculations all inform how the app evaluates your water.

When PoolFu calculates your water balance, it’s using science that traces directly to his papers. The app doesn’t just apply static ranges from an outdated chart, it implements the thermodynamic relationships he documented, adapting targets based on your actual water temperature and chemistry.

This is what he spent his retirement building: a scientific foundation rigorous enough that software could implement it correctly. That foundation now runs inside the phones of pool owners who’ve never read a chemistry paper but benefit from his work every time they test their water.

The Chlorine Lock Question

Wojtowicz’s papers also provide ammunition against persistent myths. The notion of “chlorine lock”Chlorine LockA myth. The idea that high CYA completely stops chlorine from working. In reality, high CYA just requires proportionally higher chlorine levels. It doesn’t ‘lock’ anything., the idea that high cyanuric acid renders chlorine completely ineffective, has been floating around the pool industry for decades. It originated with 1960s laboratory studies that showed cyanuric acid slowed chlorine’s kill time against bacteria.

The studies were real. Anderson in 1965 and Fitzgerald and DerVartanian in 1969 documented that CYA reduced bactericidal speed in controlled conditions. Anderson himself cautioned that his results came from laboratory conditions and should be used with caution if extended to actual swimming pool operation. Field studies by other researchers found that in real pools, with real organic loads and nitrogen compounds present, the relationship was more complex. Chlorine in stabilized pools could actually outperform unstabilized pools under certain conditions.

Wojtowicz’s papers on chlorine chemistry, the chloroisocyanurate equilibrium, and the interaction between CYA and available chlorine provide the scientific foundation for understanding what actually happens. Higher CYA does require proportionally higher Free ChlorineFree ChlorineThe chlorine available to sanitize your pool right now. This is what kills bacteria and algae. Different from combined chlorine, which has already reacted with contaminants. to maintain the same sanitizing power. The relationship is well-defined and calculable. The idea that chlorine becomes completely “locked” at some threshold is a misreading of the science.

A Life in Chemistry

Wojtowicz died on May 19, 2020, at 93. He had spent his retirement in Arizona, where he competed in the World Senior Games in Utah and the Arizona Senior Olympics. He was a Notre Dame football fan. He left three children, seven grandchildren, and three great-granddaughters.

His obituary in the Hartford Courant listed his patents, his encyclopedia chapters, his journal articles, and his book, The Chemistry and Treatment of Swimming Pool and Spa Water. It mentioned his consulting work and his service as an expert witness in chemical product liability cases. It noted that he had started his education after surviving childhood in a Depression-era orphanage.

The pool industry he contributed to so significantly after retirement rarely mentions him by name. His papers are cited in technical documents and wiki footnotes. His formulas run silently inside calculators. His corrections are applied automatically by apps that never explain where the math came from.

That’s how science often works. The person who did the foundational research fades into the background while the practical applications spread everywhere. But for those who want to understand pool chemistry at a deeper level, who want to know why we adjust alkalinity for CYA or why the saturation index matters, Wojtowicz’s papers remain the primary source.

They’re freely available. The Journal of the Swimming Pool and Spa Industry archives are hosted at poolhelp.com. Anyone curious enough to read them will find careful science, clearly documented, applicable to problems pool owners face every day.

Most pool owners will never read his papers. They’ll use apps and calculators that incorporate his work without attribution. They’ll follow advice that traces back to his research without knowing it. And their pools will be better maintained because a retired industrial chemist decided to apply serious science to a field that needed it.