TREATMENT OF SWIMMING POOLS, SPAS, AND HOT TUBS

Construction. New residential ingtound pool constmction consists of concrete/gunite 63%, vinyl liner 33%, and fiberglass and other 4% (1). The pools vary in size from 4.6 x 9.1 m ( 15 x 30 ft) to 6.1 x 12.2m ( 20 x 40 ft) and have an average volume of about 109.8 m (29,000 gal). Aboveground pools vary in diameter from 3.7 m ( 12 ft) to 7.3 m ( 24 ft), have an average volume of 56.8 m (15,000 gal), and typically have vinyl liners. The average size of commercial pools is 363.4 m (96,000 gal). 

Chlorine. Chlorine gas is used as a sanitizer mainly in large commercial pools requiring a high feed rate to maintain the desired residual. However, many pool service companies use chlorine for treatment of residential pools. Some state and local health codes specify chlorine gas as the 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Sodium Hypochlorite Solution. Sodium hypochlorite (Uquid bleach) is usually bottled as a 10—15% available CI2 solution, containing 

83% NaOH for stabiUty which has only a small effect on pool pH. It is a commonly used sanitizer for swimming pools. In pool water, it produces hypochlorite ion and hypochlorous acid  

Hthium hypochlorite sodium hypochlorite 1 Cl LiOCl NaOCl granules solution 35 10-15 

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Treatment of swimming pools, spas, and hot tubs. Waterproofing and water/oil repellency. 

WATER - TREATMENT OF SWIMMING POOLS, SPAS AND HOT TUBS] (Vol 25)... 

Feedforward -for bulk powders [POWDERS, HANDLING - BULK POWDERS] (Vol 19) -role m process control [PROCESS CONTROL] (Vol 20) -for swimming pool chemicals [WATER - TREATMENT OF SWIMMING POOLS, SPAS AND HOT TUBS] (Vol 25) -control strategy [PROCESS CONTROL] (Vol 20)... 

The oigano chlorine compounds are more expensive than inoiganic chlorine compounds, but offer improved stability against photolytic breakdown in swimming pools (21). Swimming pool sanitation is generally accomplished with 1—3 ppm free chlorine residual (see CHLORAMINES AND BROMAMINES Water, treatment of swimming pools, spas, and hot tubs). ... 

Tetrasilver tetroxide is a powerful oxidizer for sanitizing swimming pools, hot tubs, and industrial cooling system waters (see Water, treatment of SWIMMING POOLS, SPAS, AND HOT tubs). This oxide is slightly soluble and its dissociation into silver ions is enhanced by the addition of the oxidizer K2S20g. Bivalent and trivalent silver disinfectants have been shown to be from 50 to 200 times more effective as sanitizers than monovalent silver compounds. 

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