Thanks for posting this Drcast. I have been purchasing water for lighter beers (and figuring even the crappy SA water can't overpower darker beers). I really would like to learn more about water chemistry to cut down on costs and use the water straight out of the tap.
What part of the city are you in, and do you get your water through SAWS or BexarMet? I'm not sure how different their water makeups are, but it would be beneficial to know which water company makeup the numbers of your first post reflect.