The Thermo-Pondÿ Perfect Climate Submersible Pond De-icer was designed with small and preformed ponds in mind. When used as a submersible, the Thermo-Pond Perfect Climate works great in all ponds up to 300 gallons, 18 inches deep or less. When the Thermo-Pondÿ Perfect Climate is used with the Float Attachment (sold separately), it works as a floating pond de-icer, great for any pond large or small.