I recently started playing around with water test kits that are available for aquariums. In particular the GH&KH tests are useful for brewers who want to get a beter understanding of their brewing water w/o having to send a sample to an lab like Ward Labs.
I took some pictures, updated my water spreadsheet and wrote an article for my web site about this.
My local pet stores don’t carry the GH&KH only tests. They have other, more expensive, tests that include these tests. This means I had to order them online and pay $5 shipping for a $6 item.