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I was wondering what KZ Coral Snow is made of. It seems that it is pure natural chalk and water. I've made few simple tests and I'm pretty sure that it is chalk - it vigorously dissolves in acetic acid without residue, and after dehydration it looks exactly like chalk. I have natural chalk in hand and it is hard to find difference when compare with dehydrated Coral Snow. You can judge by yourself - on the picture attached - left is natural chalk and right is dehydrated Coral Snow, the stone is chalk.
Since chalk is almost pure calcite - Calcium carbonate with traces of Magnesium carbonate, silicates, ferric oxides,inorganic phosphates etc, I decide to give a try to pure calcium carbonate (analytical grade) instead Coral Snow - and it works like charm - it has the same effect, and I'm sure that there is no unwanted impurities like phosphates, silicates and ferric salts. The pure calcium carbonate is bright white, while chalk and Coral Snow have yellowish color, because of other salts.
I really like Coral snow because is helps a lot especially when new corals are added into the tank - the chalk reduces the mucus secretion from one side and coagulate organic compounds make them easily removed by skimmer or consumed by bacteria.
There are about 4 grams chalk in 10 ml of CoralSnow.