Ep 114. How To Manage Chlorine and Better Water Chemistry

During their conversation, Frank and Jacque discuss effective methods for managing the chlorine levels and water chemistry in a pool.

The Deep End Pool Podcast focuses on residential pool maintenance and may not cover commercial pool requirements. Please consult the CDC and local authorities and code requirements for commercial pool maintenance.

08:51 There are several factors that influence the effectiveness of chlorine in managing your pool, not just how many parts per million of chlorine exist in the water.

10:45 Regular water testing is crucial to ensure the appropriate levels of chlorine, including free and total chlorine, pH, and alkalinity, at least once a week. Although calcium hardness, total dissolved solids, salt levels in salt pools, stabilizers, and borates do not necessarily need to be tested as frequently, they should be checked regularly to maintain and manage proper water chemistry. If you encounter any issues, such as algae, staining, etc., requiring you to dose products for treatment, you must frequently test the water before dosing.

13:30 Frank dislikes using untestable chemicals or additives without a measurable effect or concentration.

17:15 When testing the chlorine levels in a pool, measuring both free and total chlorine levels is important, especially when there is a swimmer load on the pool. Chloramines are formed when chlorine oxidizes ammonia, nitrogen, or carbon-based contaminants in the water. They are disinfection byproducts (DBPs) that should be eliminated by using additional oxidizers. Eliminate chloramines by achieving breakpoint chlorination through additional oxidizers. OTO chlorine tests do not provide information about the amount of combined chlorine. Chloramines can irritate and are less effective at oxidizing than pure chlorine. If you only measure the total chlorine levels in your pool or spa, you may get an inaccurate idea of its oxidizing capabilities. Measuring free and combined chlorine levels separately is recommended for a more accurate reading.

24:25 To effectively manage your pool’s chlorine, you need to determine your CYA or stabilizer level. If your pool has borate levels of 40 to 50 ppm, consistently maintaining 5% of your CYA level in free chlorine is necessary. However, if you do not use borates, you must maintain 7.5% of your CYA level. Note that this percentage can vary if you also use ozone, UV, AOP, or mineral purification systems.

32:20 pH levels have a significant impact on the effectiveness of chlorine. Lower pH increases its effectiveness, while higher pH decreases its effectiveness and reduces the UV protection of CYA on chlorine. Waterfalls and turbulence from returns hitting the surface increase the rate of your pH rise and increase evaporation. If you have a dramatic pH rise from week to week, consider dosing acid for your pH more frequently.

39:00 It is crucial to conduct thorough testing and accurate calculations when determining the appropriate dosage of chemicals.

44:55 When testing alkalinity, subtract 1/3 of CYA from the test results to get adjusted alkalinity. Use this adjusted value for dosing.

46:20 Manage your CYA properly by taking steps to lower it, using borates to reduce the need for stabilized chlorine, and avoiding overuse of stabilized chlorine. Do not use stabilized chlorine when water temperatures get below 65 degrees in the off-season.

49:00 Hypochlorites, liquid chlorine, and cal hypo are high pH. However, it is unnecessary to dose extra acid when using these products.

50:40 It is not recommended to use dichlor shock in trichlor pools as it can cause excessive CYA levels in the pool.


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