How to test water hardness

  1. K3NN3TH Initiate Member

    When people talk about water hardness, what exactly do they mean?

    Should I get a test kit that tests for KH or GH or Calcium?
     
  2. mathas Well Known Member Member

    Most people are referring to GH, unless the word "hardness" is used in a specific context that would let you know otherwise.

    Dissolved calcium ions are part of the GH measurement, so a dedicated calcium test kit wouldn't help much unless you have a specific need to know calcium content.

    API makes a two-kit pack for GH and KH, which if I recall correctly, is about the same price as their other single-test packages... I think the last time I paid attention at a store, it was under $10: http://aquariumpharm.com/Products/Product.aspx?ProductID=74