The biggest misconception about salt water pools is that they don't use chlorine. They absolutely do — they just generate it continuously through electrolysis instead of requiring manual addition. Understanding this distinction, and understanding what actually changes in a salt water pool from a service standpoint, is what separates techs who can service SWG systems competently from those who misdiagnose problems every season.
A salt chlorine generator (SWG) passes pool water across titanium electrode plates with a low-voltage DC current applied. The dissolved sodium chloride (salt) in the water dissociates at the electrodes:
The chlorine gas produced instantly hydrates to form hypochlorous acid and hypochlorite — the same sanitizing chemistry as adding liquid sodium hypochlorite directly. The salt molecule is not consumed — it cycles through the process and reforms. This is why salt levels don't drop significantly over time (they do drop slowly through dilution from backwashing, splash-out, and rainwater overflow).
| Parameter | Chlorine Pool Target | SWG Pool Target | Why Different? |
|---|---|---|---|
| Free Chlorine (FC) | 1–4 ppm | 2–6 ppm | SWG output fluctuates; higher target provides buffer |
| pH | 7.2–7.8 | 7.2–7.6 | SWG generates high-pH byproducts (NaOH); pH trends upward |
| Total Alkalinity (TA) | 80–120 ppm | 80–120 ppm | Same |
| Calcium Hardness (CH) | 200–400 ppm | 200–400 ppm | Same; low CH corrodes titanium cell plates |
| CYA | 30–50 ppm | 60–80 ppm | Higher CYA compensates for chlorine output variation |
| Salt (NaCl) | N/A | 2,700–3,500 ppm | Required for electrolysis |
| TDS | Below 1,500 ppm | 2,700–5,000 ppm (includes salt) | SWG adds significant TDS from salt |
This is the most important chemistry difference between SWG and traditional chlorine pools. The electrolysis reaction at the cathode produces hydroxide ions (OH⁻), which raise pH. Additionally, the hydrogen gas produced at the cathode strips dissolved CO₂ from the water through aeration, which also raises pH.
The result: pH in SWG pools tends to drift upward continuously — sometimes 0.2–0.5 per week — without acid addition. This is why muriatic acid consumption is often higher in SWG pools than in liquid chlorine pools, despite the misconception that "salt pools require less chemical management."
Salt levels are measured in parts per million (ppm). Most SWG systems have a low-salt alarm and will reduce or shut off output when salt drops below the minimum. Each system has a unique target range:
| SWG Brand/Model | Optimal Salt Range | Low Salt Alarm |
|---|---|---|
| Hayward Aqua Rite | 2,700–3,400 ppm | Below 2,500 ppm |
| Pentair IntelliChlor IC-20/40 | 3,000–4,000 ppm | Below 2,700 ppm |
| Jandy AquaPure | 3,000–3,500 ppm | Below 2,500 ppm |
| CircuPool RJ+ series | 2,500–3,500 ppm | Below 2,000 ppm |
| Solaxx Saltron Retro | 3,000–4,500 ppm | Below 2,500 ppm |
Use pool-grade solar salt or evaporated salt (99% pure NaCl). Do not use rock salt or water softener salt with additives. Add directly to the pool with the pump running, spreading around the perimeter. Salt dissolves slowly — allow 24–48 hours and test before adjusting further. Brushing helps dissolve it faster.
The SWG cell produces calcium scale over time — more rapidly in hard water and when pH runs high. A lightly scaled cell is normal; a heavily scaled cell fails to produce adequate chlorine despite the control board reporting 100% output.
Hayward Aqua Rite and Pentair IntelliChlor cells have diagnostic readings available through the controller. The "instant salinity" reading vs the "desired salinity" reading, combined with low output at high settings, is the primary indicator of cell scale or cell degradation.
SplashLens tracks salt levels, cell cleaning dates, SWG output settings, and FC readings for every SWG account. Know when each cell is due for inspection and catch low-output issues before customers complain about green water. Free and offline.
Open SplashLens Free →No. Salt water pools use a salt chlorine generator (SWG) that converts dissolved salt into chlorine through electrolysis. The result is hypochlorous acid — the same active sanitizer as traditional chlorine pools. Salt water pools are generating their own chlorine continuously rather than having it added manually.
Most SWG systems operate optimally at 2,700–3,500 ppm salt. The specific target varies by manufacturer — Hayward Aqua Rite targets 2,700–3,400 ppm, Pentair IntelliChlor targets 3,000–4,000 ppm, Jandy AquaPure targets 3,000–3,500 ppm. Always check your specific cell model.
Most SWG cells should be inspected every 3 months and cleaned as needed — typically every 3–6 months depending on calcium hardness and pool chemistry. Pools with CH above 400 ppm or that run at high pH will scale cells faster and may need quarterly acid washing.
Common causes of inadequate FC in SWG pools include: output percentage set too low for seasonal demand, CYA above 80 ppm requiring more chlorine per target FC, scaled or degraded cell with reduced output capacity, salt level below minimum, or phosphate load consuming chlorine faster than the cell can produce it.