Tunze AquaWind Twin Aquarium Ventilator / Fan, 7028.900. **** PRODUCT MANUAL **** TUNZE® Aquawind is an especially low-noise aquarium ventilator provided with a 5 V low-voltage power supply unit. Moreover, it comes with an attachment means, which can be used for every aquarium edge up to 25 mm (.98 in.). It produces a laminar air movement over the surface of the water, accelerating the evaporation process and thus achieving a cooling of the water. In standard aquariums, the cooling may amount to 1° to 2° Celsius (1.8° to 3.6° F) on 500 litres (132 US gal.).