Be careful...Calcium Carbonate precipatation is not fun to clean up after. I learned that recently by over dosing Calcium Chloride into my cycling seahorse tank. Thank goodness that I had no life in the tank. It was quite a mess. Thats the first time I did that. I have been using raw calcium chloride to dose instead of kalk or 2part. There are no instructions so I guess it was a learning experiance.
OPPPSSSS
As for test kits I use both Salifert and Hagen. I will admit that I trust the salifert more. I just like having the option of a second test to varify outlandesh results
Scott