One of the most surprising findings from this analysis has nothing to do with chemistry.

It has to do with geography. Pool professionals often debate which sanitizer is the most economical. Some swear by liquid chlorine. Others insist cal-hypo delivers the best value. Still others point to trichlor tablets.

The reality may depend less on the chemical and more on where the service company happens to be located.

The representative pricing used in this article assumes liquid chlorine costs approximately $5.25 per gallon, a figure derived from contractor reports and market pricing outside of Florida. At that price, liquid chlorine works out to about $5.25 per pound of available chlorine, making it one of the more expensive sanitizer options in this comparison.

But Florida has long been the exception when it comes to liquid chlorine pricing. Decades of Service Industry News, price surveys have consistently shown that service businesses in that state pay well below the national average for liquid chlorine. Currently, Florida service technicians are paying about $2 per gallon.

At that price, liquid chlorine costs $2 per pound of available chlorine — cheaper than cal-hypo, trichlor, or dichlor.

In other words, the exact same chemical can move from near the top of the cost chart to near the bottom simply by crossing a state line.

Why the difference? Florida's large concentration of pools, extensive liquid chlorine distribution infrastructure and proximity to major suppliers have historically helped keep prices lower than in many other parts of the country. In other regions, transportation costs, local competition, supplier relationships and purchase volume can all have a significant impact on pricing.

There may not be a single national answer to the question of which sanitizer is cheapest.

A pool service company in Florida and a pool service company in Texas may perform the same calculations and reach completely different conclusions. Both may be correct.

That's one reason chlorine-cost discussions often generate so much debate within the industry. Service professionals aren't necessarily comparing the same market. They're comparing the prices available in their own market.

When it comes to chlorine economics, geography may matter just as much as chemistry.