Old post yes but seems to be something to it from this page. Then again it's not that clear. UV or over chlorinating then gassing off .
http://www.natureswayresources.com/DocsPdfs/chloramine.pdf
Chlorine and chloramines kill the nitrifying bacteria that fix nitrogen from the air
into the soil. Hence additional nitrogen must be supplied to the plants to rep
lace
the loss of free nitrogen from nature.
Container plants
(hanging baskets, pots, etc.)
are more susceptible to
damage
from chloramines
as they tend to require more watering.
Studies have shown that
chloramines hurt
the germination of seeds from
many
species of plan
t
s.
Chloramine is neutralized in the soil by reactions with organic matter, destroying
it in the process. Organic matter in the form of humus can hold 15 times its
weight in water, hence the soil loses some of its ability to hold and stor
e water.
Chloramine hurts the production of compost tea as it kills off some of the
microbial species that one is trying to grow to high densities. Note: One teaspoon
of humic acid
(liquid form of humate)
can neutralize the chloramines in 100
gallons of
water depending on the exact concentration of chloramines