Hello Geo...
If you're like most of us who just keep fish you can get at the local fish store, you don't need to worry about the pH, hardness. alkalinity or any of the other chemistry stuff. It's not important for keeping a healthy tank. All you need to do, is treat the water with a product that removes chlorine, chloramine and detoxifies ammonia and nitrite. Seachem's "Safe" is a good product. To maintain the tank water long term, just remove and replace half or more of the water weekly. This will maintain a steady water chemistry and this is all the fish need.
B