Well, the hard water won't hurt your fish in any way but it does tend to leave unsightly stains. If it is really bad, and really bugs you, then you could switch over to a bottled water, or get remineralized RO
from your LFS
, but that will get expensive. It would likely be cheaper in the long run to buy your own filter.
If you do switch over make sure to do it slowly. You don't want to make large changes too quickly.