What about residual toxic compounds?

Lake Guard H2O2™ breaks down simply into water and oxygen.  Within hours, no trace is left in the water of its inert, biodegradable coat. Due to these traits, it is suitable for use in natural water reservoirs as well as in potable water resources.

The Lake Guard Blue™ is composed of copper sulfate which is a heavy metal. Although it is approved for all types of water bodies by the US EPA, including potable water sources, there is a global attempt to reduce its useage. Having said that, the Lake Guard Blue™ is far more potent than the Lake Guard H2O2™, meaning it is likely to be used in extreme bloom cases, as well as in water reservoirs with less concern of copper accumulation.