and solutions to them
Algaecides are chemicals that kill algae and blue or green algae, when they are added to water. Examples are copper sulphate, iron salts, rosin amine salts and benzalkonium chloride. Algaecides are effective against algae, but are not very usable for algal blooms for environmental reasons.
The problem with most algaecides is that they kill all present algae, but they do not remove the toxins that are released by the algae prior to death.