Hot tub water balance cheat sheet
Ideal levels for chlorine, bromine, pH, alkalinity, and hardness — and the order to adjust them in.
Most hot tub water problems — cloudiness, itchy skin, that "off" smell — trace back to one of five numbers being out of range. Here's the full target chart, and (just as important) the order you should adjust them in so you're not chasing your own tail.
Target levels
| Parameter | Target | Ideal |
|---|---|---|
| Free chlorine (chlorine tubs) | 1.0–3.0 ppm | — |
| Bromine (bromine tubs) | 2.0–4.0 ppm | — |
| pH | 7.2–7.8 | 7.4–7.6 |
| Total alkalinity | 80–120 ppm | — |
| Calcium hardness | 150–250 ppm | — |
Run either chlorine or bromine as your sanitizer — not both. If you use dichlor chlorine, cyanuric acid (CYA) also slowly builds up and quietly weakens your chlorine; once it climbs past ~50 ppm, the usual fix is a partial drain and refill.
Adjust in this order
The parameters affect each other, so sequence matters. Working top-down avoids re-doing steps:
- Total alkalinity first. Alkalinity buffers pH — if it's off, pH won't hold still. Get TA into 80–120 ppm before anything else.
- pH second. With alkalinity stable, nudge pH into 7.4–7.6. This is the range where sanitizer works well and the water is comfortable on skin and equipment.
- Calcium hardness third. Too low corrodes; too high scales. Aim for 150–250 ppm — it drifts slowly, so it needs less frequent attention.
- Sanitizer last. Once the water is balanced, set free chlorine (1–3 ppm) or bromine (2–4 ppm).
A pH of 15 or a sanitizer of 50 means a misread strip or expired reagent, not your water. Acting on a bad reading is how people overshoot. And if sanitizer is already high, don't add more — wait for it to fall back into range.
Gear this guide uses
The kit to read all five numbers, plus the chemicals to move them in order.
- Start with a way to read the chart — 5-way spa test strips cover chlorine, bromine, pH, alkalinity, and hardness.
- For sanitizer, pick one path: dichlor or cal-hypo chlorine or bromine.
- To move pH and alkalinity, keep soda ash (pH up) and dry acid (pH down) on the shelf.
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Sources
General guidance — always confirm with your own test kit and your tub manufacturer's instructions, and adjust gradually.