Here's a couple of links about adding salt to calculate the water volume of a pond. I thought this would be of interest since we were discussing adding salt to a pond.

http://aquanic.org/publicat/usda_rac/efs/srac/103fs.pdf

http://www.thekoidude.com/salt.html

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.