We have hard water from our well. It is filtered twice before boiling it: by the water filter and with a manual on-the-counter filter. When boiled in a clean kettle a white substance floats in the water, and it isn't calcium which is hard and sinks at the bottom. Then we filter that hot water through a coffee paper filter and a white creamy substance remains. I called water related companies but no one knows. Anyone have a answer to this one?

  • $\begingroup$ You could always separate the white creamy substance and test it... $\endgroup$ – Eashaan Godbole Nov 7 '16 at 2:53
  • $\begingroup$ It may be an organic matter - proteins that is. Try drying it and burning it - if it turns black then it is organic. $\endgroup$ – vapid Nov 7 '16 at 8:50
  • $\begingroup$ Thank you. I'll do the drying and burning part for certain. $\endgroup$ – Pierre H. Nov 7 '16 at 18:00

I assure you it is calcium carbonate.

The particles are so small they do not just sink to the bottom like a stone. Instead, they aggregate at the nearest phase boundary. All small impurities do that, unless they have a very low interfacial tension with water. It's energetically much more favourable than sinking.

Over time, this creamy substance aggregates further, up to a point where the aggregates are large and dense enough to dissociate from the surface, and sink to the bottom.

  • $\begingroup$ Thank you Karl. This week I'll be installing a bigger water filter (adding salt to it or either potassium I'm told), hoping that it will get rid of that "calcium" as you say. If it is calcium carbonate in very small particles, then such calcium is unharmful to the body I presume. Small amount of natural calcium (126 mg/l from the analysis) can only be healthy. I really appreciate you feed back. Thank you. $\endgroup$ – Pierre H. Nov 7 '16 at 17:58
  • $\begingroup$ "adding salt to it or either potassium I'm told" What? Do you mean you have an ion exchanger like in a washing machine? That's not a filter, and I've never heard of using a Ca-Na exchanger for drinking water. $\endgroup$ – Karl Nov 7 '16 at 19:05
  • $\begingroup$ This is what they call a water softener. (Autotrol) And yes they add salt... unfortunately. $\endgroup$ – Pierre H. Nov 8 '16 at 0:12

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