How To Treat A Pond For Swimming . Use a pond rake to capture unwanted materials from the center of the pond. If you’re not sure if your pond or lake contains dangerous animal species, contact aec for a consultation. How To Identify And Treat Algae In Your Swimming Pool from www.sparklingpoolservice.net Allow the bag to sit in the pond for several weeks, preferably where the water spreads, such as a fountain or waterfall, if possible. You can buy or rent a water pump from most home improvement stores. Once the biodegradable spheres have been.