Why not talk about what brewers are looking to get from a water spreadsheet.
One challenge, which I hopefully addressed to some extend, is providing a simple interface to a potentially complex problem. That’s why I have the “basic” and “advanced” sheets in mine. They are connected such that if you start entering values into the basic sheet they are carried into the advanced sheet and you can use that if you feel you need more info. It doesn’t work the other way.
Water treatment options can be overwhelming and I don’t want to scare brewers away by having too many options. On the other hand, there are so many water treatment options and I want to be able to provide guidance and calculations for most of them. In addition to the basic addition of salts and acids I have played with dissolving chalk and, just recently, successfully applied lime treatment of brewing water. I’ll be releasing an update that includes that calculation as well.
I’m also not supporting hydrochloric acid for mash pH treatment. It is a very dangerous acid and not for casual use in brewing. If you have access to food grade HCl and not just HW store muriatic acid you are likely knowledgeable enough to do update the spreadsheet to support it. Lactic acid as acidulated malt or 88% solution is a much safer option.
Another design aspect, which I considered, is having a layout that is mobile device friendly. Many of us have handheld devices capable of running spreadshets which we are using on brewday or even for quick recipe deign. Hence the arrangement of the fields in a column on the right.
Here is the link to the current version: http://braukaiser.com/documents/Kaiser_water_calculator.xls
Just in case you don't know it already: check out OpenOffice.org which is a free office suite that also supports Excel spreadsheets.