Use Tap water always. Let it sit uncovered for 24-72 hours so the chlorine and cloramine (or whatever it is) evaporates out of the water.
I ventured down the RODI and Distilled. It's fine but more work, measuring in
Calmag. Tap water is close so you won't need
calmag. If you do notice
calmag may help while using Tap water simply up your micronutrients a teaspoon and note it in your feeding schedule.
Also, it's a good idea to get your Tap water checked for heavy metals. Just in case your plumbing is old. Cannabis is for humans and the earth. There is no other plant on earth that's better at ridding the soil of pollutants. Hence 'ditch weed.' They don't call cannabis that because it's worthless garbage, countries literally plant it in ditches to clean the soil because that's where bad stuff goes, the ditches.
Check me out on YouTube, everything's there and I keep adding more. I'm down to explaine anything so if you have questions please ask, it'll help the next guys.