try this :

http://www.minbar.com/pool_calc.html

and what i do is i have those kitchen pyrex measuring cups in 1 cup and 1/2 liter sizes and when i need to convert xxx grams or whatever units to something else (that is referenced in either beachcalc or pool_calc).. i goto www.google.com and type in:

convert xx grams to oz

and google spits out a nice answer that i can measure with my measuring cups!