BWT Water Hardnesss Test Kit

Know Your Water Before You Filter It
The BWT Water Hardness Test Kit gives you two pieces of information that are directly useful for anyone setting up or maintaining a BWT filtration system: how much calcium is in your water supply (the primary driver of limescale build-up in espresso machines and brewers), and the total hardness of your water (the figure used to calibrate the bypass setting on the BWT Bestmax and Bestmax Premium filters). Without knowing your total hardness, the Bestmax's adjustable bypass is a guess — too aggressive a setting removes minerals that support good extraction, while too conservative a setting allows calcium compounds through that cause scale. This test kit gives you the number you need to set it correctly. Both tests use a simple drop-based method: fill the test jar with water from your supply, add drops of the reagent until the colour changes, and count the drops to read the result.

Two Tests, Two Purposes
The calcium test measures the concentration of calcium carbonate specifically — the compound most directly responsible for limescale deposits on heating elements, boiler surfaces, and group heads. High calcium readings indicate a supply with significant scale risk, which is useful information regardless of which filtration solution you're using. The total hardness test measures the combined concentration of calcium and magnesium ions — the standard measure used in water filtration and the figure referenced in BWT filter documentation for bypass calibration. James from Edmonton describes it as a must-have for anyone setting up a good water system, and notes it takes very little time to run both tests. Chad from Chicago confirms the results match those from a dedicated aquarium test kit — a useful cross-reference for buyers who want independent validation of the readings. Note: as with all reagent-based test kits, check the expiry dates on the dropper bottles on receipt and use them within their rated period.

Part of the BWT Water Filtration Range at Coffee Addicts
The BWT Water Hardness Test Kit is the diagnostic starting point for the BWT filtration ecosystem at Coffee Addicts. Once you have your hardness readings, the BWT Bestmax Water Filter ($130) and BWT Bestmax Premium Water Filter ($175, with Magnesium Technology) are the plumbed-in filter options — both requiring the BWT Besthead Quick-Change Filter Head (sold separately). For tank-based machines that don't require a plumbed-in filter, the BWT Bestsave Water Softener Pad ($14) is the no-installation scale protection option.