Bromine Water Test Results Guide

What this test measures

Bromine is the sanitiser of choice for many hot tubs and spas — it keeps working at the higher temperatures where chlorine fades. This test tells you whether there’s enough active bromine in the water to keep it clean.

The UK standard

Bromine isn’t a drinking water parameter — it’s a pool and spa measure. Hot tubs are commonly maintained around 4–6 mg/l and pools around 2–4 mg/l, but always follow your manufacturer’s guidance for your setup.

Reading your strip

Dip a strip into your sample for two seconds, hold it level and wait 30 seconds. Match the bromine pad against the colour chart on your instructions card and read off the closest band. Strips give you a clear range rather than a lab-precise number — exactly what you need for spotting problems and tracking changes over time.

What to do next

• Confirm it first. One strip is a snapshot — re-test with a fresh strip and a fresh sample before acting on a result.
• Low bromine? Dose according to your product’s instructions and re-test before anyone gets in.
• High bromine? Leave the cover off, let levels fall naturally and re-test — don’t use the tub until it’s back in range.
• Check pH at the same time — sanitisers only work properly when pH is in range.
• Thinking about a filter? Test before and after fitting it so you can see exactly what it changed.