CA REHS Pools exam questions with correct solutions

2 Tests for Chlorine Levels 1. Orthotuludene- Ortho Test 2. Diethyl Phenylene Diamine- DPD Natural Bathing Place Not man-made body of water Lakes, ponds, rivers, ocean beaches Problems Associated with Bathing Places Unsanitary surroundings, pollution, water contamination Pool: adequate filtration and chlorination prevent spreading of disease Gastrointestinal disturbances, typhoid, dysentery, leptospirosis, ringworm, other skin infections, schistosomiasis (swimmer's itch), upper respiratory infections, sore throats, middle ear infections Pink/Red Eye Caused by Pools Too much chlorine or high alkalinity causes conjunctivitis Bathing Beach Sanitation Possible sewage contamination: agriculture runoffs, storm drain runoffs, animal populations Turnover Rate: Pool 6 hours, 360 minutes Turnover Rate: Spas 30 minutes Turnover Rate: Wading Pool 1 hour, 60 minutes GPM Calculation Pool Volume / (6 hours X 60 mins/hr) Fill and Draw Pool Filled with fresh water, used for a period of time, then drained and cleaned "common bathtub" 2 Disadvantages of Flowthrough Pools 1. Bacterial contamination cannot be controlled, only maintained 2. Can only accommodate 1/3 of the swimmers of a recirculating pool Flowthrough Pool Equal portion of water is replenished with freshwater on a continual basis Partly Artificial Pool Stream is dammed to create a small lake Number of bathers is limited due to coliform count Pool Water Filtration Every 6 hours or 4 times in a 24 hour period Diatomaceous Earth D.E. Most common pool filtration element used 30,000 gallons or less (medium residential size) Made from diatoms that have calcified (looks like white coffee grounds) When Should a Filter be Backwashed? When the output is 10 psi or less than the input Ex: 50 psi inlet, 40 psi outlet, backwash filter Pool Filter Calculation: 2 gpm per square foot, 30 square feet of filter area D.E. = 2 gal/ft2/min X (filter area X 2) 60 = 120 gpm filtration Cartridge Filtration Most expensive Capacity is 0.375 gpm/ft2 Must be broken down, cleaned, dried (or replaced) prior to reassembling