Chlorine removal by aeration at various temperatures was not effective. Free chlorine
concentrations in sample #3 (S3) slightly decreased from 1.66 to 1.41 mg/L in open bottle
on a dark shelf (26C) and from 1.67 to 1.43 mg/L in open bottle in a refrigerator (5C)
for 3 days. Also, for chlorine removal in water by freezing (-20C) and melting (5C),
free chlorine concentration slightly decreased from 1.68 to 1.56 mg/L in open bottle for 3
days. In an additional analysis after 1 month, however, almost the same concentration of
free chlorine as that shown on the third day was detected (1.35 mg/L in open bottle on a
dark shelf), which indicates the long residual effect of chlorine.
this doesnt seem to reconcile with common advice in relation to chlorine in aquarium water...standard practice (other than de-chlorination with chemicals) is to let tap water stand for 48 hours to de-chlorinate it prior to introducing fish ...the results above suggest this does bugger all. I wonder if the fish know this?