Nutrient management is a critical part of addressing the harmful algal bloom (HAB) crisis sweeping across the globe.Lake Erie, like many large, shallow lakes, suffers from annual cyanobacterial HABs. While phosphorus to the western basin are codified, none exist for nitrogen (a key component of toxin structure and biomass), in part due to lack of information about processing rates.This talk will discuss the knowledge gaps for nitrogen cycling in Lake Erie and the ways my research group has worked to fill those gaps over the last decade, including evaluating external and internal nitrogen loading and removal. Additionally, we are working to address a major knowledge gap—creating a predictive model for toxin concentrations—by applying internal and external nutrient processing rates and loads.