This auto-fill float assembly is designed to be installed inside of the pond.
An auto-fill is one of those features that if you install one you will love it. It makes maintaining a pond so much easier. An auto-fill does just what the name implies. It will automatically keep the pond water at the same level all the time. As water evaporates, it will automatically replaces it. They are especially useful if you have a bead filter, because each time you backwash the filter, the auto-fill will replace any water used during the process. Too often you hear of someone turning on the hose to add water and then forgetting to turn it off only to later find all their koi dead. This is because whenever you replace more than 10% of your pond water at any one time (with city water), you need to add a dechlorinater to neutralize the chlorine in the water which is toxic to fish. With an auto-fill you don’t run the risk of forgetting to turn off the water. Under normal use it is generally not necessary to add dechlorinator to the pond each time the auto-fill comes on. The reason is that you are replacing such a small percentage of water that the chlorine evaporates before it can become a problem.
Installing on a liner pond? You will need a bulkhead. (Find one here)