Discus require special water, more specifically soft water. If you live in a hard water area you can still keep happy an healthy Discus. Many will tell you that you have to setup special water purification systems in order to keep Discus and start in the hobby. This is not true and as you will see in the articles below Discus are strong fish that can live happily in varied conditions.
Below are articles focused on Discus water conditions, reverse osmosis (R.O.) purification systems and supplementary water conditioners used with keeping Discus.