CPO Operation and Maintenance

When performing a color-matching water test, when using the comparator, you should: a. hold the comparator up to direct sunlight b. be in a dimly lighted room c. wear sunglasses and hold the comparator up to the sunlight d. **hold the sample up to the northern horizon or a daylight illum...

When performing a color-matching water test, when using the comparator, you should: a. hold the comparator up to direct sunlight b. be in a dimly lighted room c. wear sunglasses and hold the comparator up to the sunlight d. **hold the sample up to the northern horizon or a daylight illuminator** **Explanation:\ When performing a color-matching water test using a comparator, you should hold the sample up to the northern horizon or a daylight illuminator. This provides consistent lighting conditions, ensuring accurate color comparison between the sample and the standard color discs in the comparator. Holding the sample up to the northern horizon or a daylight illuminator helps minimize glare and variations in lighting, allowing for precise color matching.** 2. Pools using chlorine gas as a disinfectant produce hydrochloric acid, which can be neutralized with: e. sodium thiosulfate f. cyanuric acid g. **caustic soda or soda ash** h. carbon dioxide **Explanation:\ Pools using chlorine gas as a disinfectant can produce hydrochloric acid. To neutralize this acid, caustic soda or soda ash is commonly used. These substances help maintain the pH balance of the pool water and ensure it remains safe for swimmers.** 3. The only physical factor that affects water balance is: i. pH j. TDS k. **temperature** l. calcium hardness **Explanation:\ Temperature is the only physical factor that affects water balance. Temperature influences the saturation index, which is a measure of the water's tendency to deposit or dissolve calcium carbonate. As temperature increases, the saturation index tends to decrease, leading to the potential for scaling or corrosive water conditions. Adjustments to other parameters like pH, total dissolved solids (TDS), and calcium hardness may be necessary to maintain proper water balance in response to changes in temperature.** 4. A spa with an 8′ diameter having a water depth of 2′-8″ will contain pounds of water. m. 1.003.37 n. 1,117.39 o. **8,307.49** p. 8,370 39 **Explanation:\ Solution.: Volume (lbs.) = 3 14 x r x r x depth x 62.4\ lbs = 3 14 x 4 x 4 2.67 x 62.4 = 8,370.39** 5. A round pool with a 25′ diameter contains square feet of surface area**.** q. 39.25 r. 78.5 s. **490.63** t. 1.962 50 **Explanation:\ Solution: A= 3.14 x r x r\ A = 3.14 x 12.5x 12.5 = 490.63** 6. To be classified as a disinfectant, a compound must kill or inactivate 99.9% of contaminants as well as: u. maintaining proper water balance v. **leave a measurable residual in the water** w. have an NFPA classification of x. have a sweet-smelling aroma **Explanation:\ To be classified as a disinfectant, a compound must not only kill or inactivate 99.9% of contaminants but also leave a measurable residual in the water. This residual ensures that the water remains protected against microbial growth and contamination between treatments. A disinfectant with a measurable residual helps to maintain water quality and safety over time, providing ongoing protection for swimmers.** 7. A round pool with a 20′ diameter and a water depth of 5′-4″ contains gallons of water. y. less than 12,400 z. between 12.400 and 12,500 a. **between 12,501 and 12,600** b. more than 12,600 **Explanation:\ Solution: Volume (gals.) = 3.14 x r x r x depth x 7.50\ Gals = 3 14 x 10x 10 x 5.33 x 7.50 = 12,552.15** 8. A spa with water tested as pH 7.2, temperature 103, calcium hardness 600, total alkalinity 120, and TDS of 1,500 will be: c. **scale forming** d. balanced e. corrosive f. sanitized **Explanation:\ With a pH of 7.2, temperature of 103°F, calcium hardness of 600 ppm, total alkalinity of 120 ppm, and total dissolved solids (TDS) of 1,500 ppm, the water is likely to be scale forming. A pH of 7.2 is within the acceptable range, but the high calcium hardness and total dissolved solids levels indicate a potential for scale formation, especially in a hot environment like a spa. Adjustments to reduce calcium hardness and TDS may be necessary to prevent scaling issues.** 9. A rectangular swimming pool measuring 30′ long by 15′ wide with a water depth of 3′ on the shallow end and 6′ on the deep end will contain gallons of water. g. less than 15.000 h. between 15,000 and 15,100 i. **between 15.101 and 15,200** j. more than 15.200 **Explanation:** **Solution: Ave depth = 6 + 3 ÷ 2 = 4.5 \