CaCl2 Q

[njmar1]

Greetings,

Been perusing the forum and don't know if this was answered, but if it has please point me to the right discussion:

Was planning to get CaCl2 in bulk for a group buy but was told by another reefer that long term it's not good since the Cl2 levels will build up. I am assuming that epsom salts will neutralize this- how does this occur? Will the Cl2 ions be held in a complex in the water itself and still build up?

[Randy Holmes-Farley]

Chloride (Cl-) can build up over time using it alone.

Epsom salts don't neutralize it, but since it is magnesium sulfate, it keeps magnesium and sulfate from depleting relative to sodium and chloride.

These issues are discussed in these articles:

This one describes how to use CaCL2 and Epsom salts together with baking soda to make a 2 part additive syswtem:

A Homemade Two-Part Calcium and Alkalinity Additive System
http://www.advancedaquarist.com/issues/april2004/chem.htm

These two describe what happens with CaCl2 alone:

Simulating the Effect of Calcium Chloride and Sodium Bicarbonate Additions on Reef Systems
http://web.archive.org/web/20010210224240/http://www.animalnetwork.com/fish2/aqfm/1998/dec/bio/default.asp

Additional Simulations: The Combined Effect Of Calcium Chloride
/Sodium Bicarbonate Additions And Water Exchanges
http://web.archive.org/web/20030624150320/http://www.animalnetwork.com/fish2/aqfm/1999/feb/bio/default.asp