Everything I read about what chlorine does to soil microbes that are in place to protect plants, makes perfect sense to me.  I have been constantly amending my soil with Miracle Grow Garden Soil, and now they keep making improvements to it, like adding pellets that hold the moisture to the soil and release it slowly, when needed.  I just felt that if I kept putting down more good soil, I could offset the chlorine in the water that I give my plantings.  For a very long time this system has worked well for me, because we have very hard clay soil, and nothing was growing well, before I began amending it about six years ago.  Now even my topiary rose trees are growing so well, that I do not have to bury them for protection against the harsh winters.   I think perhaps the dechlorinator that works for you, might be worth a try.  It would certainly be cheaper, over time, then what I am constantly paying now for numerous bags of garden soil.