Circulation Systems & Basic Hydraulics Water Loss • Evaporation • Splash-out • Drag-off • Maintenance procedures • Intentional disposal • Leaks Signs and Symptoms of Leaks • More than 1/4 inch of water is lost in 24 hours • High water bill • Algae growth, discolored water, or inability to balance chemicals • Loose or popping tiles • Cracking of deck, settling of pool • Constant running of automatic fill device • Large amounts of air in the pool • Wet spots that never dry • Uneven grass growth around the exterior of the pool Detecting Water Loss • Bucket test • Use of dyes to test for suction leaks • Pressure testing lines • Professional instruments which use sound to find leaks Water Loss Per Inch V = LWD, where D = 1” 1” = 1/12ʼ = .0833 Example: A 25 yard by 25 meter pool loses 2 inches of water per day. How much water must be added to the pool per week to make up for this loss? (75) (82) (.0833) = 512.295 cubic feet x 7.48 = 3,832 gpi x 14 = 53,648 gallons Water Clarity • 0.25 NTUs - Nephelometric Turbidity Units • 0.2 Jackson Turbidity Units • 0.6 - cloudy pool, 1.0 - unacceptable • Recirculation system should be capable of returning pool water to acceptable levels within 6 - 8 hours • Methods for determining clarity: • Nephelometer or turbidometer • 6 inch black disk • Paneled disk • Main drain grates • Quarter--heads or tails Consecutive Dilution Turnovers 5 4 3 2 1 % Water Clarity 99 98 95 84 2 Days to Equilibrium 1 2 3 4 9 Turnover Time • 6 or 8 hours Swimming pools • 2 hours Training & therapy pools • 1 hour Wading pools • 30 minutes Spas • Requirements may vary by State Relationship between Flowrate and Turnover Time Flow Rate 360,000 gallons of water ÷ 360 minute required turnover = 1,000 gpm flow rate Turnover Time 360,000 gallons of water ÷ 1,000 gpm flow rate = 360 minutes = 6 hour actual turnover time Bather Load & Clarity Keep the bather load to total filtered water (gallons/day) ratio at 1 bather : 1,400 gallons or less