Algal bloom

 You can check for algal blooms in a pond by looking for signs like a film on the surface, murky water, or dead fish. You can also test the water for algae using a sampling kit or laboratory analysis. 

Signs of an algal bloom

Film on the surface: Algae cells often sit at the water's surface 

Murky water: Cloudy water can indicate increased algae cells 

Odor: As algae cells bloom they release odorous gases 

Foamy water: Foamy water can be a sign of a harmful algal bloom 

Globs or mats of algae: Globs or mats of algae can be a sign of a harmful algal bloom 

Paint-like appearance: If it looks like paint was spilled on top of the water, that can be a sign of a harmful algal bloom 

Dead fish: When you often see dead fish in your lake or pond, then it's likely the water is unhealthy 

Testing for algal blooms

Sampling kits: You can purchase sampling kits to test for algae in your water 

Laboratory analysis: You can send a sample of your water to a lab for analysis 

Enzyme-linked immunosorbent assay (ELISA) tests: You can use ELISA tests to determine if the algae bloom produces toxins