Tables from our Acqua Perfetta Kit booklet: reference values, glossary and doses of the most used products.
Ideal values for private pools
ParameterValue
Water hardness (TH)from 200 to 300 mg/L
Alkalinity (TAC)from 150 to 250 mg/L
pHfrom 7 to 7,4
Free chlorinefrom 0,5 to 2 mg/L
Stabiliser≤ 50 mg/L
Phosphates< 0,1 mg/L
Copper< 0,1 mg/L
Iron< 0,1 mg/L
Recommended parameters and tolerances
ParameterToleranceUnitNotes
pHfrom 6,9 to 7,7pHPools with fresh water treated with chlorine.
Active free chlorinefrom 0,4 to 1,4mg/LPools with cyanuric acid ≤ 15 mg/L.
Available chlorinefrom 2 to 5mg/LPools with cyanuric acid ≥ 15 mg/L.
Combined chlorine≤ 0,6mg/LMaximum tolerated level of chloramines.
Cyanuric acid≤ 75mg/LMaximum tolerated level of stabiliser.
Glossary
Hardness (TH)It is determined by the presence of calcium and magnesium ions (limescale). At high concentrations water is hard, at low concentrations it is soft. Hard water, when heated, forms a deposit known as scale or limescale.Measured as: calcium
Alkalinity (TAC)Pool water must have a minimum alkalinity level (carbonate and bicarbonate ions) to keep the pH stable. It can drop because of acid rain or because of excessive, sudden additions of acidic products.Measured as: alkalinity
pHIndicates the acidity of the water on a scale from 0 to 14. Neutral pH is 7: lower values indicate acidic water, higher values basic water. It affects bather comfort and the effectiveness of many disinfectants.Measured as: phenol red
PhosphatesThey come from pollution or the decomposition of plant material (leaves, grass, pine needles). Dissolved in water, they are a major source of nutrients for algae and promote their growth, together with bacteria.
Free chlorineIt depends on the amount of chlorine added: it is the sum of active chlorine, responsible for disinfection, and potential chlorine.Measured as: DPD1
Active free chlorineIt is the fraction of chlorine immediately active depending on pH: it is the part responsible for the disinfecting action.
Combined chlorineIt comes from the reaction of chlorine with nitrogenous substances brought in by bathers, which form chloramines: they irritate the eyes and give off the smell of chlorine. An adequate free chlorine level (about 2 mg/L) helps reduce them.Measured as: (DPD1 + DPD3) − DPD1
Total chlorineIt is the sum of free chlorine and combined chlorine.Measured as: DPD1 + DPD3
StabiliserCyanuric acid protects chlorine from the sun’s ultraviolet rays, slowing its breakdown. However, an excessive concentration impairs disinfection and requires partial or total water replacement.Measured as: Cya
Balance and active chlorine
Draw a straight line between the measured hardness (TH) and alkalinity (TAC) values: where it crosses the central scale it indicates the equilibrium pH. Example: TH 280 mg/L and TAC 130 mg/L → pH about 7.4.
Active part of chlorine depending on pH, with water at 27 °C and an unstabilised pool. Columns: measured free chlorine (mg/L); rows: pH.
