sanitation for spas - prozone - ozone & advanced … marketing article.pdf · ity of ozone...

SANITATION FOR SPAS

SPA FOCUS

December 2009 ▪ Pool & Spa Marketing ▪ 67

MERGING HIGH-TECHNOLOGY SYSTEMS

BY RON BARNES

The combination of ozone and chlorine/bromine generation automates spa sanitation and reduces the time and effort re-quired to maintain clean and healthy water.©Dreamstime.comO

ver the past several years, salt chlo-rine generators have become an established sanitation method in the swimming pool

industry. While most companies offer a range of products for swimming pools, few have addressed the spa market. Homeown-ers who have these systems installed on their pool are looking for the same equipment for their spa. Unlike pools, spas without ozone or automated systems have complicated dynamics that require constant attention by the end user. As a spa sanitizer, ozone has been the treatment of choice since the mid-80s as few

other chemicals or systems can exceed its capabilities. Homeowners want ease of auto-mation, similar to what a salt chlorine/bro-mine generator offers; however, salt systems alone do not meet the load requirements of a spa without necessitating excessive chlo-rine/bromine residuals. Ozone combination systems solve this dilemma by providing an automated sanitation system, which meets consumer demand and offers improved water quality. In response to these demands, the practice of combining ozone, advanced oxidation and salt chlorine/bromine generators has continued to increase, as these systems ad-dress the requirements of spa dynamics and sanitation.

A COMBINATION OF BENEFITS

The combination of ozone and chlorine generation offers spa owners a number of ben-efits. These systems automate spa sanitation and significantly reduce the time and effort required to maintain clean and healthy water. Ozone, a powerful oxidizer and sanitizer, kills bacteria and viruses and reduces bather load by causing it to precipitate for removal by filtration. However, because ozone is utilized quickly, a residual cannot be established to provide constant bather protection (the major-

ity of ozone produced reacts at the point of contact). Residual sanitation is provided by the chlorine/bromine-generating portion of the system, which protects bathers in the water from the transmission of waterborne diseases. Other benefits include reduced chemical handling and the assurance spa water remains clean during periods when it is not being used.

CHLORINE/BROMINE GENERATION

The first step in the chlorine/bromine genera-tion process is the introduction of salt. Only spa-grade salt should be used, as additives in food-grade and other types of salts will cause clouding of the spa water and possible equip-ment problems. Salt concentrations vary by manufacturer, with some systems operating in the range of 1,800 to 2,200 parts per million (ppm). For example, a 1,135-L (300-gal) spa would require approximately 3.1 kg (7 lbs) of salt. This is ideal for minimizing corro-sion potential. When used in conjunction with ozone, a halogen residual of 1 ppm is needed. Electrolysis systems, which do not use ozone, require much higher salt levels (3,000 ppm), as the requirement for chlorine/bromine is also higher (3 to 5 ppm) to sanitize the spa on its own. The complete sanitation system includes:1. Pure ozone generation2. Advanced oxidation processing (AOP)3. Salt-to-halogen electrolysis generation (chlorine/bromine).

WHAT DOES THE SYSTEM DO?

The most powerful oxidizer and sanitizer available is the merging of ozone and AOP, which combine to form hydroxyl radicals and peroxides. As water passes through the filtra-tion system, the radicals and peroxides create the maximum amount of sanitation possible and produce clear, odourless water with no harmful byproducts. However, a small amount of chlorine is needed for higher bather loads, as all of the water will not enter the filtration system. Ozone and AOP will destroy a majority of contaminants, leaving the chlorine residual free to attack the remaining contaminants. Even with a free residual as low as 0.5 ppm, the combination of a halogen, such as chlorine/bromine, with an ozone system offers outstanding sanitation of biologically heavy bather loads.

Spa sanitation is optimizedby combining pure ozonegeneration, AOP, and salt-to-halogen in one easyinstallation (or system). Photos courtesy Prozone Water Products

BENEFITS OF USING A COMPLETE SANITATION SYSTEM IN A SPA

• Provides highest sanitation level, combining ozone, AOP and halogen (chlorine/bromine) generation;• Controlled chlorine/bromine production;• Improves water quality and clarity;• Reduces required level of chlorine/bromine;• Reduces chlorine/bromine consumption;• Reduces required amount of salt level;• Reduces chemical costs; and• Reduces maintenance.

68 ▪ Pool & Spa Marketing ▪ December 2009

SPA FOCUS

Together, these technologies provide proper sani-tation while reducing the amount of chloramines in the spa water. The need to control chlorine residual is also minimized.

THREE INTEGRATED TECHNOLOGIES

When combining pure ozone generation, AOP and salt-to-halogen systems, the methods used to gain the most out of spa water sanitation are simpli-fied. Even though complete sanitation is reduced to one system, it still possesses all the individual benefits that were gained when each system oper-ated separately.

1. The complete sanitation system uses UV ozone generators to produce pure ozone, which is free from highly corrosive chemicals such as nitrogen oxide (NOx) and nitric acid (HNO3). These chemicals are highly corrosive to stainless steel, vinyl and neoprene rubber. Pure ozone destroys resistive biologicals, biguanide byproducts, foaming and odours. It also oxidizes contaminants, converts chloramines to free chlorine, neutralizes metals and produces clear water. It does all of this while it pro-duces breakpoint (complete oxidation), allowing sanitizers to produce a load-free residual.

2. AOP is ozone and humidity in the presence of germicidal UV, which produces hydroxyl radicals that are more powerful than ozone, because it has a much higher oxidation potential. This added reac-tion increases the oxidation potential of the system, which is capable of destroying highly resistant chemicals such as halogenated compounds, insec-ticides, pharmaceuticals and biologicals including Cryptosporium (Crypto), Giardia, fungus, mould and other viruses. Introducing the AOP/ozone into the halogen salt generator cell, which energizes the halogens to a higher reactive state, can produce further AOP. It is introduced into the spa via a standard bypass configuration.

3. Through electrolysis, salt chloride/bromide is converted into chlorine/bromine.. Properly designed systems use the following:

• Multiple ruthenium-coated titanium plates for longevity;• Microprocessor-based voltage control;

WHEN COMBINING PURE OZONE GENERATION, AOP AND SALT-TO-HALOGEN SYSTEMS, THE METHODS USED TO GAIN THE MOST OUT OF SPA WATER SANITATION ARE SIMPLIFIED.

• Automatic plate reversal to clean calcium buildup;• High-temperature construction materials;• Pulse width modulation to control halogen output levels;• Optional redox (oxidation reduction potential [ORP]) control; and• Provisions to clean the cell with muriatic acid.

UNDERSTANDING AOP OZONE AND SALT CHLORINE/BRO-MINE GENERATORS

Although AOP ozone and salt chlorine/bromine generating systems are syner-gistic and self-compensating, three operational modes are available:

Type INon-controlled chlorine/bromine production—at the water’s breakpoint with low chlorine residual.


SPA FOCUS

Type IIVariable control chlorine/bromine production—above the water’s breakpoint with the potential for high chlorine residual.

Type IIIClosed-loop control—an automatic controller main-tains a chlorine/bromine or redox residual. All three systems operate under the premise that the ozone satisfies the oxidation requirements of the water (breakpoint). Breakpoint happens when all of the combined chlorine/bromine has been eliminated and only the free chlorine/bromine remains. In other words, breakpoint occurs when all of the oxidizable loading of the water has been satisfied.

OPERATING RESIDENTIAL SPAS ON COMBINED OZONE AND HALOGEN

Type IWith a spa’s fast turnover rate and short-term tran-sient high bather loads, the fast reaction of ozone provides complete sanitation. However, recovery time for sanitation and ORP is somewhat slow. Free chlorine and ozone react to oxidizable materi-als in the water, which in turn raises the ORP to provide a high sanitation level. As such, a low free-chlorine residual is required. Operating near the breakpoint provides a high sanitation level without

high chlorine levels. In this state, the amount of free chlorine and chloramines (combined chlorine) are low enough they may not even be detected. This system was tested to National Sanita-tion Foundation (NSF)/American National Standards Institute (ANSI) Standard 50 – Equipment for Pools, Spas, Hot Tubs, and Other Recreational Water Facilities and passed at 0.5 ppm halogen.

Type IIWith this operational mode, ozone meets all of the oxidation requirements of the spa water, allowing free residual chlorine to begin accumulating. It will accumulate until the mechanism of dissipating the chlorine, e.g. off gassing, heat, UV light agita-tion, etc., limits the maximum free chlorine residual. As chlorine becomes available it is used up in highly loaded spas. This mode can have variable outputs depending on the circumstance and desired effect. In cases where high bather load occurs, this system can be used in high chlorine mode to provide light shock capabil-ity and high free chlorine residual. In residential systems, high chlorine levels are undesirable. In this case, the Type II system can operate in Type I mode, automatically operating below breakpoint.

Type IIIThis operational mode uses an automated control system to

.Retrofit Installation

Combine the PZ1 with Prozone’s automated salt chlorine/bromine generator with cell for a complete sanitaion system. Salt cell may be

easily retrofitted to an existing PZ1 system!

Using a bypass with dual port injector and in-line electroly-sis cell, a complete sanitation system (CSS) simplifies the combination of technologies into one system for OEMs and retrofit installations.


SPA FOCUS

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

measure and operate the generation of ozone and/or chlorine to provide sanitation. ORP or redox controllers measure and control the level of sanitation in the water. In this case it is necessary to meet breakpoint if a chlorine residual is desired. If ozone is not limited, the ORP controller will allow the ozone to provide all of the sanitation requirements with little to no chlorine residual.

INSTALLATION

The best way to install a spa salt chlorine combi-nation system on a spa is with a bypass dual-port venturi arrangement. This method provides a simple original equipment manufacturer (OEM) or retrofit installation as the most efficient method for introducing ozone and chlorine into the spa’s circulation system. The use of a dual-port bypass also allows the spa owner or service person to clean the chlorine cell without removing it from the spa. Suction created by the venturi is used to draw muriatic acid into the system to remove any calcium, which is not removed by the automatic reversing cycle from the chlorine generating cell. Ozone only spas may be easily upgraded to com-plete sanitation systems.

CELL DESIGN

In earlier cell designs, single electrodes of carbon and stainless steel were used for electrolysis. These plates had a short lifespan, poor chlorine produc-tion and were not reversible. Modern plates are made of titanium and coated in ruthenium (similar to platinum) , on both sides, which is durable, efficient and more expensive. Polarity can also be reversed to remove calcium deposits. These electrolysis cells use a series of stacked plates, which increases efficiency and system life. These plates are connected to a solid-state power supply. The voltage differential created between the plates converts the salt water—containing chlorine/bromine ions—into energetic molecules of sodium hydroxide and sodium hypochlorite. Depending on cell design variations, e.g. plate number, size and the amount of halogen (chlo-rine/bromine) to be produced, the voltage must be precisely controlled. Variable levels of salt change the loading and must be compensated for in the power supply. To prevent overdriving the system and damaging the plates, the reversal cycle must be timed with the cell loading to remove calcium deposits.

RUN THE SYSTEM

The next step is to simply run the system, which


SPA FOCUS

will immediately start generating chlorine/bro-mine through electrolysis. Though system operation is simple, consum-er and dealer education is extremely important. Typically, these systems are connected to the spa’s control pack and operate with the circula-tion system. Some manufacturers utilize topside con-trollers to provide preset run times based on specific conditions. The circulation time and chlorine controller determine the amount of chlorine generated, which is typically a high-low knob found on the Type II unit. In any case, run time is critical to obtaining the best results. For optimal spa water sanita-tion and clarity, a minimum of eight hours per day is essential for both ozone and chlorine/bromine generation. Water quality problems can occur when us-ing run times of less than six to eight hours per day. This cuts chlorine production and does not allow sufficient ozone to be introduced into the spa water (ozonation effectiveness is also dependent on run time). Extending the length of the filter cycle will mitigate frequent spa draining, while monthly shocking using dichloride or sodium hypo-chlorite is a good preventive procedure. Do not confuse this with the commonly used term ‘shocking,’ which generally means adding more chlorine than normal. Adding chlorine in amounts less than the volume required for

super chlorination does not achieve the same effect; in some cases it can even be counterpro-ductive. ‘Non-chlorine’ shocks do not shock the water when used with ozone and can create chemical byproducts that are harmful to the spa. Calcium hypochlorite is not used as it increases calcium deposits on the electrolysis plates. Low chlorine readings are normal under high-load conditions and are not indicative of sanitation limits. For spa water testing, DPD liquid test kits work best, as opposed to test strips. The best indication of proper operation is water clarity. If cloudy or odourous condi-tions persist, drain or shock the spa, check the filter and operate the complete sanitation system continuously for 48 hours. Increased run times of 12 hours are recommended for spas with higher bather loads.

With more than 30 years of experience in water sanitation, Ron Barnes is the founder and CEO or Prozone Water Products located in Huntsville, AL. He holds numerous patents in ozone and combina-tion systems. He can be

reached at [email protected]


THE PRACTICE OF COMBINING

OZONE, ADVANCED OXIDATION AND SALT CHLORINE/

BROMINE GENERATORS HAS

CONTINUED TO INCREAS, AS THESE SYSTEMS ADDRESS

THE REQUIREMENTS OF SPA DYNAMICS

AND SANITATION.

With a spa’s fast turnover rate and short-term transient high bather loads, the fast reaction of ozone provides complete sanitation.

SPA FOCUS

sanitation for spas - prozone - ozone & advanced … marketing article.pdf · ity of ozone...

Documents