Many municipal water supplies now started to add Chlorimine to the water to stabilize the chlorine. This disinfectant is formed by mixing chlorine with ammonia
. Chloramine is a less effective disinfectant than chlorine, but it is longer lasting and stays in the water system as it moves through the pipes that transport it to your home. Chloramine is often used alongside chlorine as a “secondary” disinfectant designed to remain in your water longer. API water conditioner is a basic product and does nothing to kill the Chloromine. API Stress Coat and Prime cost more but work. Not all water conditioners are created equal and many aquarists have been finding out the hard way. Leaving water to age is a good way to get rid of chlorine but does nothing to the chloromine. You can find out if your water supply has started to add this to the water. You can find out more info on Chloromine here. Ive even started not to drink my local tap water because its a very powerful dissinfectant that I would rather not have in my body.