martiniduck
Aquarium Advice Activist
I have hard water and when doing weekly water changes I use tap water that is "softened" by a water softener. I understand that the water from my tap is not really softer, the calcium ions have been exchanged for sodium ions. During the winter months the tank evaporates as much as an inch per week. Even with the water changes there has to be a build up of minerals in the water. My fish are fine and I do not see any signs of stress, but should I add some RO or distilled water to the tank to lower the hardness? How do other handle this?