Managing eutrophication and mitigating cyanobacteria blooms has been a hot topic for over 100 years. Tackling cyanobacteria blooms remains a challenge. The purpose of this thesis was to investigate various potential compounds and techniques to manage eutrophication and mitigate cyanobacteria blooms. By five different experiments across different scales, ranging from laboratory to field observations, I learned each lake possesses unique characteristics, and each in-lake intervention has its limitations. Therefore, conducting a system analysis of individual lakes is the initial step in managing eutrophication and cyanobacterial blooms. Controlled experiments under realistic conditions across different scales are needed before a field application can be carried out for a successful restoration plan. An independent institute testing materials and techniques for in-lake interventions could be useful to fill the tool-box with effective and safe measures.