# 8.3.1 Control of algae Algicides are used to reduce toxic or odorous algal blooms in water reservoirs. The chemical commonly used in the management of algal growth is copper sulfate. Before an algicide is used, the possible effects on aquatic biota, the accumulation of copper in sediments, the potential impacts on downstream treatment processes, and final treated water quality should be considered. The use of copper as an algicide is controlled in some states. Information on the use of algicides should be obtained from the appropriate state or territory authority (see Section 8.9). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://guidelines.nhmrc.gov.au/australian-drinking-water-guidelines/part-2/chapter-8/8.3-overview-of-chemical-treatment-processes/8.3.1-control-of-algae.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.