Sodium Bromide is not technically an algaecide, but is used with granular chlorine  as a catalyst to convert the bromides into the potent algae killer, hypobromous acid.  Bromides are usually used not for algae control, but to kill pool algae in out-of-control cases.

Also known as Sedoneural, sodium bromide has been used as a hypnotic, anticonvulsant, and sedative in medicine, widely used as an anticonvulsant and a sedative in the late 19th and early 20th centuries. Its action is due to the bromide ion, and for this reason potassium bromide is equally effective.

Adverse effects related to bromide therapy include neurologic deficits polyphagia, polyuria, polydipsia, and vomiting, and bromide use may be associated with the development of pancreatitis.

Sodium is a positively charged radical, which is very unstable because it is a highly reactive metal. Even to protect it for its reactivity, it is kept inside kerosene oil.

SODIUM BROMIDE LR