If you guys can't be bothered calculating how much star-san to dilute, I made this simple calculator (http://www.thebrewlist.com/calculator/sanitiser-dilution). Also calculates PBW, Iodophor and OxiClean.
The ratios I use:
5gal water =
1 fl oz Star-san
1.5 oz PBW
0.5 oz Iodophor
1.0 oz OxiClean...