Do these filters remove calcium etc which create limescale - in other words would they be suitable for my espresso machine which is particularly sensitive to limescale formation?

Lime scale/calcium is considered a mineral and will be read as such . – With regards the TDS reading and minerals in the water. Our technology does not remove ionic minerals from the water - it does however remove sedimentary minerals. In order to reduce the heavy metals, we use several types of media in our formulation that have a specific affinity for heavy metals. We do not include however, any media in our formulation that would remove beneficial minerals. Because the media formulation does not have an affinity for beneficial minerals such as calcium and magnesium, these minerals pass right on through the elements. When you test the post filtered water with your TDS meter, you are verifying that the beneficial minerals have not been removed. The ppm that is being registered in the post filtered water indicates the parts per million of beneficial minerals that remain in your water.