Scottish Water has recently started adding chloramine to water in the Aberdeenshire area, and fishkeepers and retailers are being urged to ensure their water is properly dechlorinated.
The Invercannie treatment works, which serves Aberdeenshire, was upgraded on October 1, while the Inverness treatment works has been adding chloramine to the tapwater supply since February.
More than 10% of the UK's tapwater supply now contains added chloramines, and a growing number of water authorities are making the switch from using chlorine to disinfect the tapwater they provide.
Compared to chlorine, chloramines are much more stable. While chlorine may remain in the water for a few days, and needs to be added at high levels to allow for losses, chloramine doesn't and can persist for several weeks, even when strongly aerated!
Unlike chlorine, chloramine can't be removed by boiling, leaving the water to stand, aerating it, or spraying it into the aquarium or pond through a hose, and unless you take the appropriate steps to get rid of it, it will remain in the water.
When given a sufficiently long contact time (5-10 minutes) chloramine can be removed from water using a combination of activated carbon and zeolite. Some RO units will remove it, when equipped with carbon filters. However, the easiest way to remove it is to use a chemical water conditioner.
The majority of popular dechlorinators are based on an ingredient called sodium thiosulphate, in varying strengths. When added to water containing chlorine at the correct dosage, these water conditioners convert the chlorine to harmless chloride ions, making the water safe to use.
Several ingredients used in other dechlorinators, including sodium sulphite, sodium bisulphite and ascorbic acid, as well as sodium thiosulphate, can also remove monochloramine from tapwater.
However, many need to be used at double the normal dose for chlorinated water, and the vast majority of them also leave behind the ammonia part of the chloramine molecule, unless an additional ingredient has been added to take care of it. So, while you'll get rid of one toxin, you could potentially introduce another simply by treating the water.
Two products, Kent Ammonia Detox and API Ammo-Lock2 are capable of removing chloramine and the resulting ammonia. The vast majority of other dechlorinators do not do this.