From
http://reefkeeping.com/issues/2005-01/rhf/index.php :
"One interesting aspect of limewater is its ability to self purify before being added to the aquarium. This happens in several ways, but all relate to the fact that most aquarists dissolve it and then let any undissolved solids settle out. Few, if any, of these solids are then dosed to the aquarium. It turns out that these solids can contain many of the impurities that came to the limewater, either in the solid lime, or in the water itself. In a recent article I showed experimentally and theoretically how this process works for a variety of metals, including copper, nickel, and cadmium.
Figures 1 and 2 show experimentally what happens when solid lime is added to water that contains a significant amount of copper. In the high pH of limewater, copper precipitates from solution as copper hydroxide. It also turns out that excess lime solids themselves can help remove additional metals from solution, as those metals bind to the surfaces of the undissolved lime. Besides metals, other impurities can also be precipitated from limewater as calcium salts, including phosphate."
That being said, I wouldnt replace DI with kalkwasser. I'd still run both. [/B][/QUOTE]
No doubt....
but still very interesting......