Fish and pond life require oxygen-rich water to remain strong and healthy. The beneficial bacteria in your filtration systems also need oxygen to flourish and keep your pond free from the build-up of toxic waste. Aeration is especially important through the warmer months where water holds less oxygen. Oxygenating plants produce oxygen during the day, however, they start to use oxygen at night, which depletes your pond of oxygen. The Blagdon Pond Oxygenator dramatically increases the level of oxygen and reduces carbon dioxide in the pond, whilst aiding in the overall circulation of your pond to prevent stagnation. It can also be used in the winter months to help keep an area ice free, preventing the buildup of toxic gases which can be fatal to fish and wildlife. This model does not come with air stone and airline. Please Note- due to UK Building Regulations, these units do not come fitted with a plug.