Salt chlorinators are the default on new Cape Town pools. The cell only works inside a narrow salt band, and most salt dosing guides online are written in US gallons and pounds.
Here are the numbers in litres and kilograms.
Ideal Salt Level for a Pool
Most chlorinators run best at 3,200 ppm, within a working band of 2,700 to 3,400 ppm.
Check your cell manual. A few high-output systems want up to 4,500 ppm, but 3,200 ppm suits the majority of units sold in South Africa.
- Too low and the cell underproduces, then the pool goes green
- Too high and the cell can trip or corrode over time
How Much Salt to Add to a Pool: The Formula
The calculation is simple in metric.
Salt in kg = pool litres x (target ppm minus current ppm) / 1,000,000
A 40,000 litre pool reading 2,200 ppm, aiming for 3,200 ppm, needs a 1,000 ppm lift. That is 40,000 x 1,000 / 1,000,000 = 40 kg.
Pool Salt Chart in Litres
| Pool volume | +500 ppm | +1,000 ppm | Empty to 3,200 ppm |
|---|---|---|---|
| 20,000 L | 10 kg | 20 kg | 64 kg |
| 30,000 L | 15 kg | 30 kg | 96 kg |
| 40,000 L | 20 kg | 40 kg | 128 kg |
| 50,000 L | 25 kg | 50 kg | 160 kg |
| 60,000 L | 30 kg | 60 kg | 192 kg |
Pool salt here is usually sold in 25 kg bags, so a 50,000 litre pool filling from empty needs roughly six to seven bags.
How Many Bags of Salt for a 50,000 Litre Pool
From zero to 3,200 ppm, about 160 kg, which is six and a half 25 kg bags.
Topping up by 1,000 ppm on the same pool needs 50 kg, so two bags.
How to Add Salt to a Pool Correctly
- Switch the chlorinator off, leave the pump running on filter
- Broadcast the salt across the shallow end, never down the skimmer
- Brush it along the floor so it does not sit in a pile
- Allow 24 hours of circulation before you trust a reading
- Switch the chlorinator back on once it has dissolved
Undissolved salt lying on a marbelite or fibreglass floor can mark the surface. Brush it out.
Why Pool Salt Readings Drift in Cape Town
Salt does not evaporate. It only leaves the pool with the water.
- Backwashing removes salted water, so the level drops
- Winter rain overflow dilutes it
- Splash out over a busy summer adds up
- Topping up from a wellpoint changes the reading
That is why salt usually needs correcting twice a year rather than monthly.
Swimming Pool Salt: What to Buy
Use pool-grade salt. It is a coarse, high-purity sodium chloride that dissolves cleanly.
Do not use table salt with anti-caking agents, and do not use coarse industrial salt with high impurity levels. Both can cloud the water or stain the surface.
If your cell is old and the salt reading is correct but production is poor, the cell plates may be scaled or worn. Our team services and replaces chlorinator cells as part of pool equipment repairs.
How Much Pool Salt Do I Need From Scratch
A new or freshly filled pool starts at close to zero. At 3,200 ppm target you need about 3.2 kg of salt for every 1,000 litres, so a 40,000 litre pool takes around 128 kg.
Pool Salt Calculator in Litres: Worked Example
A 30,000 litre pool reading 2,700 ppm needs 500 ppm more. That is 30,000 x 500 / 1,000,000 = 15 kg, which is one 25 kg bag with some left over.
Get Your Pool Salt Level Tested in Cape Town
Dosing works when the starting reading is right. A cheap strip that is six months old will send you in the wrong direction.
Our team tests water on site across Cape Town and the Winelands. We balance the pool properly and tell you what it actually needs, not what a generic chart says. Request a free quote or browse our pool maintenance services.
