I just started using my first ever bottle of Prime. I've never had to deal with chloramines, just old school chlorine. With a hose, if you pour it in so it splashes, most of the chlorine vanishes as gas. In the new house though, while the water is chemically fantastic for the fish I keep, they seem to sometimes have a heavy hand with chlorine. I dose for the amount I add only.
For decades, with chlorine, I let it gas off and as long as I stayed below about 30%, it worked just fine. Delicate rainforest fish would breed the next day, unbothered. The dechlorinator doesn't cost too much, so I am trying it.
I sure won't use it as an after-shave though. Man, it smells bad. I wish I could get plain old Sodium thiosulfate, but no one around here carries it.