This pump has been supplying aeration to a 5'x10' outdoor pond for about a year including one winter. The pump includes a 20' hose, one air stone, and a float that wraps onto the hose to suspend the air stone at a specific depth. The float is an ugly white distraction, but the float should be used if your pond is more than about 3 feet deep, otherwise the pump will be working too hard and may burn out prematurely. If you use the float, you may want to tie a weight to the air stone, with the weight able to reach the pond bottom, otherwise the wind will blow the float around. Our pond is only about 30" deep. With the air stone resting on the pond floor, it emits a steady stream of bubbles about 18-24" across when it breaks the surface, with the motor at about 3/4 speed. I put the pump in a small plastic shoebox with a lid, with a small hole cut in the side of the box for the power cord and tubing to pass through. It's important that air "leaks" into the box, remember it's pumping air which must be freely available. If your pump is at or below water level you must use a back flow preventer, or your pump could get damaged during a power outage. A back flow preventer will reduce the air flow rate. The pump is quiet, although there is a small hum which can be heard up to several feet away on a quiet day. According to the package, the pump uses only 35W (that's less power than a small incandescent light bulb). Even though it's low power, it's much more effective at aerating the water than a fountain or a waterfall, which typically can have motors up to a few HP (each HP is 750W). Our pond is in northeast New Jersey and has a dozen common goldfish. The fish love the bubbles, they often hover inside the plume before zooming off to another part of the pond. In winter the aerator maintained a hole in the ice until temperatures became subzero, but even if the hole became closed the important thing was that the air was still pumping under the ice. The aeration keeps the water "oxygenated" and prevents toxic gases from building up under the ice (due to decaying vegetation, fish feces, etc.). The fish hibernate in the deepest part of the pond below the air stone level, where they can rest without disturbance. As the water gets cold, they move slowly and stop eating. During the warm months we feed them daily with dried fish flakes from the pet store. After a power blackout, the airflow had dropped noticeably due to pond slime on the air stone, but the slime can easily be removed using a soft brush. Make sure the pump is running when you scrub so you're not pushing slime into the small holes in the air stone, and after scrubbing the airflow should immediately recover back to normal.
