pH
A numerical scale reflecting the balance between acid and alkalinity in the pool. pH 6 = high acid, pH 8 = high alkaline. Recommended pH is 7.2 – 7.6. Below 7 staining can occur, above 7.6 sanitisers don’t work, algae blooms nicely and scale formation is promoted.
Sanitiser
A chemical that kills germs in pool water. Usually chlorine but there are others. Adequate sanitiser levels ensure a healthy pool.
Shock treatment
A large dose of sanitiser applied when pool is stressed due to increased chemical demand, weather or heavy bather loads. Must be done weekly to assist normal sanitiser dosing and ensure pool water is hygienic.
Algae
Algae is a plant which loves high pH levels. Not dangerous but unsightly, easily controlled by adequate sanitiser levels and correct pH.
Stabiliser (“sun-protection”)
Ultra violet rays destroy chlorine. Stabiliser holds onto chlorine to protect it from the sun, but too much interferes with sanitiser performance (see Stabiliser “Balance”).
Stabiliser “Balance”
The level of stabiliser in the pool. Ideal range is 30ppm – 50ppm. Overuse of stabilised chlorine leads to imbalance and poor sanitation.
High stabiliser levels are known as “Chlorine lock”.
Aimflow
The jet where water returns to the pool from the filter.
Weir
The suction point where water exits pool to go through the filter (where the pool cleaner hose is plugged in).
Multiport valve
Handle on a sand filter that directs the flow of water through the circulation system. (Filter, backwash etc.)
Filtration
The process by which dirt, leaves and other material is removed from pool water. (Sand filters are the most common)
Suction leak
A point where air is sucked into the filter system. Suction leaks reduce filtration and circulation efficiency.
Total Dissolved Solids (TDS)
The amount of suspended chemical and other material in pool water. High TDS interferes with chemical action in the pool.
Oxidation
The process whereby dissolved organic material like body fluids, oils are destroyed or “burnt up”. Chlorine is a powerful oxidiser.
Total Alkalinity (TA)
A scale measuring the ability of the water to resist big changes in pH, known as “pH-bounce”.
Ideal range = 80 – 120ppm.
“Free” chlorine
Not all chlorine in water is “free” to perform its intended function. Only Free Chlorine works. Incorrect pH, suspended dirt and excessive stabiliser levels can inhibit the availability of free chlorine. Ideal range = 1 – 3ppm.