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1 Chlorine Generators Fact vs Fiction Presented by Marty Fisher Overview What is a Chlorine Generator? Liquid Chlorine Some Facts. How Salty is A Saltwater Pool? Types of Acceptable Salt. Saltwater Pool Facts. Advantages of Saltwater Pools. Can You Make Money? What is a Chlorine Generator? Equipment which generates chlorine by passing an electric current through a process of electrolysis through a saline solution. Salt (Sodium chloride) + water. Page 1

2 Types of Chlorine Generators Chemical manufacturers All pool chlorine. At the pool (or spa) systems Generate chlorine in or near the pool or spa. Commercial systems High schools Fitness centers Water parks. Types of Chlorine Generators At the Pool units Brine Systems Salt in a container near the pool. Salt Water Systems Salt in the pool or spa water. Residential Pools and Spas Commercial Pools and Spas Residential System Page 2

3 Commercial System Chlorine Production In a Saltwater Pool or Spa Electrolysis Electric current is passed between an anode and a cathode in a mild saline (salt) solution. Chlorine Production In a Saltwater Pool or Spa Anode Chlorine gas given off dissolves almost instantly in the water. Cathode Hydrogen given off produces sodium hydroxide. Chlorine gas + Sodium hydroxide sodium hypochlorite or Liquid chlorine. Page 3

4 Chlorine Production In a Saltwater Pool or Spa Sodium hypochlorite solution is PPM (depending on flow) in the cell housing. ph approximately 7.9 Start with Mild Salt Water Electrolysis of salt in water produces chlorine gas and sodium hydroxide. 2NaCl + 2H2O Cl2 + H2 + 2NaOH Salt + Water, converted by electrolysis = Chlorine Gas + Hydrogen Gas + Sodium Hydroxide The H2 (hydrogen) bubbles off. Electrolysis Recap 2NaCl + 2H2O Cl2 + H2 + 2NaOH Chlorine gas and sodium hydroxide combine to produce sodium hypochlorite, salt and water. Cl2 + 2NaOH NaOCl + NaCl + 2H2O NaCl + 2H2O = Salt + Water Page 4

5 Recap Cl2 + 2NaOH NaOCl + NaCl + 2H2O (salt + water) Sodium hypochlorite when added to water produces hypochlorus acid. NaOCl + H2O HOCl + NaOH And Then Cl2 + 2NaOH NaOCl + NaCl + 2H2O (salt + water) Sodium hypochlorite when added to water produces hypochlorus acid NaOCl + H2O HOCl + NaOH And THEN NaOCl + H2O HOCl + NaOH (hypochlorous acid) Hypochlorus acid does its job of oxidizing: HOCl HCl + O (simplified) The residuals combine NaOH + HCl Page 5

6 We Start All Over! The residuals combine NaOH + HCl to form salt + water NaOH + HCl NaCl + H2O How Salty is the Water? The Ocean 30,000 ppm Human Teardrops 8,000 to 9,000 ppm as salty as sea water Saltwater Pool 27.5lbs per 1000gal of water at start up = 3,500 to 4,000+ ppm salinity 1/10 as salty as seawater Taste Test ⅓ to ½ ounce in one gallon of water How to Test for Salt Good Test Strips Better Liquid Test Kits Best Electronic (digital) Page 6

7 The Right Stuff Pure Sodium Chloride Solar Salt Mill Grade Salt Pool Salt (Swimming Pool Distributors) The WRONG Stuff Soda Salt Food or Restaurant salt May contain phosphate based anti caking agents! Yellow Prussiate of Soda Creates cyanide gas! Potassium Chloride Salt is NOT Corrosive In older,and some newer, pools with existing electrolyses, salt will accelerate the process. Use zinc balls annually to protect older pools with copper plumbing. Make sure that all bonding lugs are attached. Watch high chlorine levels. Chlorine (Chlorimine) is one of the most corrosive chemicals used in pools. Conditioner (isocyanuric acid) will reduce the corrosiveness of chlorine. Page 7

8 General Chemistry Maintain a salt pool as you would a normally chlorinated pool. When the swimming pool chemistry is maintained at normal levels, the Electrolytic cell requires very little attention. If the pool gets out of balance the cell will require frequent cleaning. General Chemistry Cont. CHL ph Alk CYA In regions with excessively high temps, higher CYA levels may be necessary. TH (Total Hardness) below 500 PPM TDS (Total Dissolved Solids) PPM Incompatible Chemicals Bi guanines Systems Soft Swim, Baquacil Metal (copper/silver)algaecides Phosphates, or phosphate based chemicals Phosphoric or phosphonic acid based chemicals Certain types of clarifiers and sequestrates Nitrates Page 8

9 Maintenance (residential) Self cleaning systems are not maintenance free systems. On average, a self cleaning salt system needs to be cleaned one to three times a year. Water chemistry will determine how often the cell will require maintenance Maintenance (Commercial) Annually check for Phosphates and remove Maintain proper ph & Alkalinity Commercial Cells have up to a 30,000 hour operational life requiring as little as one cleaning. Cell Cleaning Clean the cell as soon as it s needed. Acid to water mixture is 1 part acid to 3 parts water. Soak cell until all calcium has been removed. Rinse cell with fresh water before returning to cell housing. Pour cleaning solution back into pool. Page 9

10 Troubleshooting Low or No Chlorine Production. Phosphates!!! Incorrect sizing, insufficient filtration run time. Low salt, low or no stabilizer. High ph, High alkalinity. Cold water. Dirty or dying cell. Troubleshooting Premature Cell Failure Excessive chlorine production. (no ORP control) Incorrect sizing. Poor water chemistry. Poor cell maintenance. Cell Abuse Page 10

11 Proper Cell Maintenance Phosphates Cause & Effect on Salt Systems What are Phosphates? Nitrates and phosphates, along with carbon are considered macro nutrients. Primary foods for algae. Attention has been focused on removal of nitrate in pools where algae is present. Recent studies show that orthophosphate, NOT nitrate, is the real limiting nutrient in algae growth. This is because nitrogen and carbon compounds, which are plentiful in the atmosphere, can be absorbed from the air by algae. Page 11

12 What are Phosphates? Phosphorus compounds are not abundant in the atmosphere. Once orthophosphate is removed from the water, the algae have no way of obtaining the nutrient it needs and dies. Phosphate Origination Phosphates are primarily found in municipal water supplies. Phosphates can also come from farm runoff, fertilizers, bather wastes and detergents. Phosphate Effects When phosphates are present in pool water, the production of chlorine from electrolytic salt systems is severely reduced. This is caused when the orthophosphate bonds with the anode/cathode (plate) of the electrolytic cell. The build up of phosphates continues on the cell until the system reverses polarity. Page 12

13 How Much is Too Much? Electrolytic cell plates begin experiencing loss of chlorine production at levels of 60 PPB of phosphate. Algae will begin to thrive at levels as low as 125 PPB. Pools with high levels of phosphate, e.g. 1000ppb will often have obvious algae blooms and may require more than one treatment of a phosphate remover. Algae, But No Phosphate? In cases where pools have excessive algae, it is possible to register a very low or zero phosphate reading on the algae plant. This phosphate is now organically bound so is not measured by the test. When the algae dies, after super chlorination and/or an algae treatment, this organically bound phosphate will be released into the water where it will eventually return back into orthophosphate. Phosphate Testing Phosphate test kits are available through most wholesale distributors. Use only fresh kits and replace annually any reagents, strips, or tablets. If possible, to assure accuracy, use two different types of kits to verify the level of phosphates. It is recommended that any algae or metals (copper, silver, or iron) present in the pool be removed prior to testing. FOLLOW THE INSTRUCTIONS! Page 13

14 Phosphate Removal Determine that a pool has phosphate levels of 60 PPB or higher. Test the level of phosphates with a reliable test kit. Try to use more than one type! Before beginning ANY phosphate removal switch the salt system Off during the phosphate removal process and hand feed chlorine if necessary. Phosphate Removal Treat any algae BEFORE phosphate treatment is started. Algae will hide the presence of phosphate. Use a phosphate remover following the manufacturer s directions. After Phosphate Removal After the phosphates have been removed, shock the pool. Use a non chlorine shock like monopersulfate. Switch the salt system ON and resume normal operation. Test annually for phosphates. Page 14

15 Saltwater Advantages Constant shocking High chlorine, low ph at the anode 10 to 30 ppm chlorine at the cell. Swimmer comfort No chloramines, no odors, Swimmers eyes, hair, skin Water has a softer feel. Automation No periods of low chlorination some manufactures are incorporating salt systems into their control systems. Saltwater Advantages Lower acid demand, Chlorine is produced at 7.9 ph not Improved water clarity Thank YOU! Any Questions? Page 15