Sorry, I can't resist,,,,
1) Clorine is one of the 16 elements that plants use/require
2) If Cloromines are used ( and they are now in most cities) They do not evaporate so air stone bubbling, leaving sit out all useless, They are removed either with charcoal filters or ascorbic acid.
3) perhaps read this ?
http://www.gardeningknowhow.com/gar.../information-on-chloride-and-plant-growth.htm