Total Alkalinity Test Results Guide

What this test measures

Total alkalinity is your water’s buffer — its ability to soak up acid without the pH lurching around. Low alkalinity means unstable pH; high alkalinity pushes water towards scale and cloudiness.

The UK standard

There is no legal limit for alkalinity in UK drinking water — it’s a balance measure rather than a contaminant. In pools and hot tubs it’s commonly kept around 80–120 mg/l, which is enough buffer to hold your pH steady.

Reading your strip

Dip a strip into your sample for two seconds, hold it level and wait 30 seconds. Match the alkalinity 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.
• If your pH readings keep drifting between tests, low alkalinity is the usual culprit — sort the alkalinity first and the pH becomes much easier to manage.
• Persistently high alkalinity often travels with hardness and scale — testing hardness alongside gives you the full picture.
• Thinking about a filter? Test before and after fitting it so you can see exactly what it changed.