Which method is used to control the growth of algae and protozoa in water?

The most effective method for controlling the growth of algae and protozoa in water is through the addition of copper sulfate. Copper sulfate acts as an algaecide, inhibiting the biological processes within algae, thereby effectively reducing their populations in aquatic environments. This method is widely used in various water bodies, including drinking water reservoirs, fish ponds, and lakes, where the control of these organisms is necessary to maintain water quality and ecosystem balance.

Filtration can help in removing some particulate matter, including dead algae and protozoa, but it does not actively control or prevent their growth in the first place. Similarly, aeration can improve water quality by increasing oxygen levels, which supports aerobic microorganisms and can potentially outcompete algae, but it doesn’t directly manage the population of algae or protozoa. The addition of nitrates may inadvertently encourage more algae growth as they are nutrients that can fuel algae blooms, rather than control them.