just curious..

Im curious as to how much calcium is in a gallon of water that has one tablespoon of pickling lime added?

I found this on the moreless site
"Calcium hydroxide can be mixed at approximately 2 teaspoons [5.7g Ca(OH)2] per gallon (or 1.5g/L) of filtered freshwater to attain approximately 800mg/L calcium solution to be dripped slowly into the reef aquarium."

Does this mean that two teaspoons of pickling lime in one gallon would yeild 80O mg of calcium per gallon? this seem low.

thanks