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View Full Version : Real differences between calcium hydroxides?


FrankMcD
01/06/2007, 11:59 AM
A question I have is about Kalkwasser, I have been using Calium hydroxide for a while and have been thinking about getting kalk stirrer. I had been using kalk from Warner Marine that dissolves cleanly, recently I got kalk from mississippi lime company (food chemical codex grade calcium hydroxide, snowflake) and I am not as happy with it, it seems dirty, and does not dissolve as well. When mixed with RO/DI water it is not the typical milky white that I have attributed to calcium hydroxide, but rather milky white/brown a tanish color, like I put a little dirt in the mix. Also there is a lot that does not dissolve left in the bottom of the container. This also takes 2-3 times as long to clear / settle after mixing. Is this a good product, is there a better choice? Why is it so dirty looking and take so long to clear up/ settle? With all this in mind I am reluctant to put this in a kalk stirrer. I picked this up after reading the article you wrote What Your Grandmother Never Told You About Lime. I like the idea of being able to use other sources, that are less costly, but do they all have similar issuse? Do you have any suggestions?

This is the webpage discribing Mississppi's product: http://www.mississippilime.com/products/product.asp?dept%5Fid=310&pf%5Fid=310181

Randy Holmes-Farley
01/06/2007, 12:49 PM
The calcium oxide (not hydroxide) that I have from the Mississippi Lime Company mixes white, but all of these grades may have impurities that could impart color (iron, for example).

I personally would not worry about a food grade lime, although if the residue is colored, I'd remove it more often than if it is white.

I discuss grades of calcium hydroxide here:


What Your Grandmother Never Told You About Lime
http://reefkeeping.com/issues/2005-01/rhf/index.htm

specifically here:

http://www.reefkeeping.com/issues/2005-01/rhf/index.php#3