Rush from Nashville, Mi writes
The amount of time it takes Crystal Blue Copper Sulfate varies, depending on multiple factors. According to the information provided by the manufacturer on the product label:
"Water hardness, water temperature, the type and amount of vegetation to be controlled, and the amount of water flow must be considered in using this product to control algae. Begin treatment soon after plant growth has started. If treatment is delayed until a large amount of algae is present, larger quantities of this product will be required. Generally, larger quantities of this product will also be required to control algae growth when water temperatures are low (below 60ºF), in hard water, and in water that is free flowing. If possible, curtail the flow of water before treatment and hold dormant for approximately three days after treatment, or until the algae have begun to die. For best results, treat algae on a sunny day when the heavy mats of filamentous algae are most likely to be floating on the surface, where it can be sprayed directly. When in doubt about the concentration required for control, first use the lower concentration. If needed, gradually increase to the higher concentration until the algae are killed."
Answer last updated on: 05/30/2021
