Use one Mosquito Dunk for up to 100 sq.ft. of water surface, regardless of depth. They can be used whole or broken into portions and applied to standing water found near the home such as: bird baths & potholes, roof gutters, flower pots, unused swimming pools, ponds, ditches, outdoor tubs, wherever water collects. To prevent from being washed away, the Dunks can be anchored usinga string tied through the center hole or they can be staked.