The Edge - Quarter 4, 2008 - (Page 19)

cozy, being in a pool where the swimmers are elbow-to-elbow is not. A common load in a spa would have one person in 100 to 400 gallons of water. Pools tend to have at least 10 times that amount of water for every swimmer. Consider this: two bathers in a 400-gallon spa are roughly equivalent to 150 people in a 30,000-gallon pool. This significant bather load can decrease the sanitizer levels very quickly. As a result, many places set regulatory limits on the number of bathers in spas. A common standard for public spas is one bather per one square meter of surface area. Because of the lower water volume in a spa, chemicals need to be measured precisely and the water tested more often. Misjudging the required dosage can drastically alter the chemistry in a small volume of water. For this reason, there are chemicals specifically designed and labeled for treating spas. These lower the risk of adding too much or not enough of a particular chemical. Because of the smaller volume and increased wastes, the water in a hot tub or spa should turn over every 25 to 45 minutes when the system is running with the proper fi ltration. The water in a pool might turn over in six to 12 hours. The faster turnover rate can take a toll on the spa’s fi ltration system, particularly if the chemicals are not in proper balance. As a result, maintenance on the fi lter will need to be performed more frequently. A hot tub or spa, with its small water volume and higher water temperature, uses up the sanitizer residual very quickly. This is why maintaining a higher level of sanitizer is necessary in hot tub water. The chemical standards reflect this fact. The spa’s water volume means that even small additions of sanitizer and other chemicals can have an immediate effect on the pH of the water. If the wrong amount of a chemical is added to a pool, there is a little time before the chemical circulates throughout the entire system. To avoid costly equipment damage, the sanitizer should be measured carefully and the pH tested frequently. The pH fluctuation can also cause bathers to be irritated and the water to be cloudy or foamy. Treating a spa the same way you treat a pool will not work. Because of the higher temperatures and smaller volumes, a new set of rules comes into play. Understand the unique features of spa water chemistry to ensure bather safety and lower risk of damaging expensive equipment. | Joe Sweazy is technical sales and services manager for HACH Company/ETS Business Unit, manufacturer of AquaChek test strips. He has published more than a dozen articles on pool and spa water chemistry and has presented numerous seminars at conferences of the Association of Pool & Spa Professionals, NESPA and more. The two big differences—higher temperature and smaller volume—cause a number of other differences that need to be taken into consideration. THE EDGE 19

Table of Contents Feed for the Digital Edition of The Edge - Quarter 4, 2008

The Edge - Quarter 4, 2008 Contents The President’s Message New Pool/Spa Federal Safety Act Worried About the 2009 Market? Treating Hot Water? Project Focus The 411 on UV Disinfection for Pools and Spas The Advantages of Seeding Aggregate Surfaces Pool and Spa Industry Wins Gold Choosing a Retirement Plan To Get Best Coverage at Lowest Cost - Shop Now Index of Advertisers

The Edge - Quarter 4, 2008

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