It's best not to mess with your hardness. Many well meaning fish keepers do much more harm than good trying to get perfect water for their fish when the water they have will do just fine. Most often some LFS employee or website says that a certain fish comes from water that has xx pH and hardness requirements. So said fish keeper tries their best to meet those requirements. But most fish acclimate to whatever water you currently have (and if you got them locally, they have already been acclimated.)
So when said fish keeper tries all kinds of chemicals and methods to change their water chemistry to whatever native wild conditions the fish's ancestors came from and then plops their store bought fish into them, all kinds of strange things happen. The fish all of a sudden have to adapt to a totally foreign environment (again) adding unwarranted stress. So, now if they survive all these sudden changes, you have to do water changes...
It's a never ending cycle of re-acclimatization and unwarranted stress. It's best to stick with your native water from whatever source you get it from unless you have a very specific reason for doing so (breeding wild angels comes to mind) and have the knowledge, wisdom, and resources to get it right every time (hardness shock is a killer.)