During the first two weeks and last two weeks of this period, as the water in the distribution system transitions from chloramine disinfectant to free chlorine and then back to chloramines, customers who use kidney dialysis machines should be aware that their water may contain chlorine, ammonia, and/or a mixture of the two. During the middle six weeks, the water should contain free chlorine only. Other specialized users of water, such as fish owners, stores and restaurants with fish aquariums and holding tanks for fish and shellfish, along with hospitals, blood/dialysis clinics, or users of home dialysis equipment may need to take action to maintain appropriate water quality during this temporary switch in disinfection. These users are encouraged to contact an appropriate professional for guidance on how to use the equipment during this period. The temporary change in treatment may have adverse effects on dialysis machines and may be harmful to fish and aquatic mammals if not properly addressed.