I am brewing my first all grain tomorrow and was wondering where I could find the most accurate water calculator. I use beersmith2 software and have compared with others online and get different results? I know there are certain factors involved like what equipment you use, dead space, cooling loss etc...but since I have not used my equipment, I am not sure. I was also wondering what most of you do as far as measuring your water. Say your recipe calls for 4.67 gal. of mash water....do you guys just round up to 5 gal. or eye ball a little over 4.5 or do you break it down and put in exactly what it calls for?? (I dont have much for measuring except for a 4 cup measuring cup and my 10 gal. brew kettle that has the gallons marked on it). Also wondering if there are any preferences on the best water to buy at the store since my tap water is horrible. Any help appreciated.