PH Scale
The PH scale is the acid and alkaline range, it goes from 0 (acid) to 14 (alkaline). The optimum PH level for swimming pools should be 7.4 which is the same as that of the human eye.
If the PH value is lower than 7.4 then PH plus (Sodium Carbonate) should be added by pre-dissolving the product first, at a rate of 100g per 10m2 to raise the PH by 0.1.
If the PH valve is higher than 7.4 the PH Reducer (Dry Acid) should be added by pre-dissolving the product first at a rate of 100g per 10m2 to lower the PH by 0.1.
Once the PH treatment has been added re-check the value approximately 8 hours later and if necessary added more product. Swimming can commence straight away after treating the PH level.
A low PH level can damage the mechanical components of the swimming pool, irritate the eyes and cause damage to the pool liner.
A high PH level can hinder the chlorine disinfection, cause skin irritation and also cause the pool water to go cloudy.
Note: Dosing rates may vary depending on the manufacturer/brand, always read the label before applying chemicals to swimming pool water.
Alkalinity
This usually comes in granular form. The Alkalinity acts as a stabiliser for the PH. If it is not at the correct level, which should be between 80 – 100, then the PH will be susceptible to irregular readings.
To raise the alkalinity, sodium bicarbonate (alkalinity increaser) is used. As always pre-dissolve the chemical in a bucket of pool water before adding to the swimming pool. To raise the TA by 10 mg/L, dose 180 g per 10 m³ into a separate bucket, and add the solution directly into the pool water.
To lower the alkalinity either use Hydrochloric acid, which is liquid form, or Sodium Bisulfate, which is granular.
When using hydrochloric acid, it needs to be poured directly into one place in the deep end of the swimming pool, for dosing rates follow the chart below:
|
Water Volume In Litres |
Water Volume In Gallons |
Reducing By 10ppm |
Reducing By 25ppm |
| 4,545 | 1,000 | 100ml | 250ml |
| 9,090 | 2,000 | 250ml | 625ml |
| 22,700 | 5,000 | 500ml | 1.25ltr |
| 45,450 | 10,000 | 1.00ltr | 2.5ltr |
| 68,175 | 15,000 | 1.5ltr | 3.75ltr |
When using Sodium Bisulfate, it needs to be pre-dissolved in a bucket of pool water first then, as with hydrochloric acid, poured into one place in the deep end of the swimming pool, for dosing rates follow the chart below:
|
Water Volume In Litres |
Water Volume In Gallons |
Reducing By 10ppm |
Reducing By 20ppm |
| 4,545 | 1,000 | 71g | 142g |
| 9,090 | 2,000 | 145g | 283g |
| 22,700 | 5,000 | 363g | 709g |
| 45,450 | 10,000 | 709g | 1445g |
| 68,175 | 15,000 | 1077g | 2183g |
Note: Dosing rates may vary depending on the manufacturer/brand, always read the label before applying chemicals to swimming pool water.