Crystal Aquatics Pool Operator Test
Questions With Verified Answers.
Alkalinity - answer✔Ideal 80-120 ppm
Total alkalinity is water's ability to resist pH changes
If high, add muriatic acid
If high, water scales: clouds water, blocks filters, white film
If high, pH drifts upward
If low, add sodium bicarbonate
If low, water is corrosive: stains surfaces, pits concrete, dissolves metal
If low, pH bounces and is difficult to maintain
Backwashing - answer✔The process of reversing filtration so that water enters from bottom of
filters and lifts debris from filter media out to backwash line
Calcium hardness - answer✔Ideal level 200-400 ppm
Calcium hardness: measure of calcium concentration in water
High Ca and Mg concentration = hard
Low Ca and Mg concentration = soft
If high, dilute with soft water
If high, water is scaling: clouds water, plugs filters, creates white film
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If low, add calcium chloride
If low, water is corrosive: pits concrete and etches plaster
Calcium hypochlorite - answer✔Solid chlorine, HTH, raises calcium concentration
Chlorine gas - answer✔Most effective, 100% FAC, dangerous
Circulation - answer✔Determined by flow rate, measured using a flow meter
Components: main drain, pump and monitor, surge tank, vacuum ports, valves, return inlets
Circulation system of pools with gutter system - answer✔Vacuum ports, valves, return inlets
Color code for filter room - answer✔Yellow = influent lines
White = effluent lines
Red = Heater lines
Black = Backwash line
Orange = Vacuum line
Blue = fill line (fresh water)
Combined chlorine - answer✔Abbreviated CC's, a.k.a. chloramines. Free chlorine acts with
contaminants to form these.
Total chlorine - free chlorine = combined chlorine
TC - FC = CC
If CC is above 0.2 ppm, super chlorinate pool
Contact time - answer✔CT values: amount of time necessary for inactivating pathogens in the
water
CT inactivation level / Chlorine level = time required to inactivate
Cyanuric acid (CYA) - answer✔Water conditioner that stabilizes chlorine after exposure to UV
radiation
Maintain at 30 - 50 ppm
Not effective with bromine
More CYA = longer it takes to kill bacteria