In 2014 the City of Toledo issued a "do not drink" advisory when toxin concentrations at the Lake Erie water intake exceeded recommended safety levels. The "Toledo incident" was just one symptom of the excessive algal growth that has been plaguing Lake Erie with increasing frequency since the early 2000s. In 2012 Canada and the United States updated the Great Lakes Water Quality Agreement with commitments to control these resurgent harmful algal blooms (HABs). In this presentation we look back at management efforts to reduce HABs in the 1970s-80s for lessons on how best to move forward under the updated Agreement.