HCA: Hermit Crab Association

HI all! For a long time I have been using Kirkland signature bottled purified water for my hermie's freshwater dish, but recently I read it closer and discovered it had "minerals added for taste" That's not safe...but is it?
I really hope I haven't been feeding my hermies dangerous water!
Thanks!

It is likely not harmful, but also may not provide all the ground minerals needed for long term health. We recommend treating tap water with a dechlorinator (SeaChem Prime is a commonly used brand) for the fresh water - then adding a marine salt (Instant Ocean is a commonly used brand) for the salt water. The 'water' care sheet explains it all.