To remove a residual taste or odor from a piscicide treatment, you should treat the water with what?

Activated charcoal is the appropriate treatment for removing residual taste or odor following a piscicide treatment due to its highly porous structure, which allows it to effectively adsorb a wide range of contaminants, including chemicals responsible for undesirable tastes and odors. This adsorption process works well in aquatic environments, helping to purify the water by trapping these compounds in the charcoal's surface.

In contrast, the other options do not function as effectively for this specific purpose. Sand filtration primarily serves to remove suspended solids and larger particulates, but it does not target dissolved chemicals that might cause taste or odor. Reverse osmosis is more suited for removing a broad range of dissolved substances, but it involves a complex process that may not be necessary or efficient solely for taste and odor removal. Chlorination could alter the chemical composition of the water but might not effectively eliminate the specific residues from piscicides, and it could introduce new tastes or odors of its own.

Therefore, activated charcoal is considered the most effective and appropriate method to address residual taste or odor after a piscicide treatment.