Open Field Collective (OFC) is a citizen-science project to monitor algal bloom in water bodies in different parts of the world. Harmful algal blooms produce toxins in water bodies and are detrimental to the health of marine animals, people, and the overall environment. OFC provides an opportunity to middle school students and their teachers to learn about the diversity of the microscopic world in water, specifically harmful algae, and the basics of frugal science tools to monitor them. OFC provides training on the use of microscopy (including foldscopes) and spectroscopy to visualize harmful algal species and measure their abundance over an extended period of time. OFC currently includes participants from India, Bangladesh, and the US and is always looking for collaborations to expand its reach to monitor water quality in different parts of the world.