Well yes... After a few days, in sunlight especially, the chlorine will go away. But distilled water is a whole different thing. It is boiled super hot, then the evaporated "steam" is collected. It has no minerals or ANYTHING in it. So it also has a bad buffering capacity. That means that it is not stable enough to maintain ph, and that the levels in the water will fluctuate. I don't reccommend using distilled. Use tap with a dechlorinator, or use spring water-- which you may have to treat as well.