The Versiflow line of pumps from Matala are excellent for Heavy and continuous flow duty. They can be installed vertically or horizontally, are fully submersible and handle solids up to 3/8". 2 year manufacturer warranty.
Pondmaster Pond-Mag Pumps are made to run continuously, because they don't have seals that can wear out. These pond pumps are extremely energy-efficient, and the resulting savings pass directly on to you. This type of pump is suitable for large fountains, piped statuary and ponds.