-50% on a selection of fish food
Temperature governs the appetite and growth of fish. Choose an aquarium heater first by the actual volume of water: the product page for the EHEIM thermocontrol, for example, recommends 100 W for 100 to 150 L and 200 W for 300 to 400 L, with the next size up in a cool room. Without water movement, the heat stays around the tube: a filter or an air pump distributes it. External heaters, such as the JBL ProTemp e, fit on a filter's outlet hose and heat the tank, the filter and the grow beds together, up to 600 L.
In summer, the problem is reversed. A cooling fan lowers the water by 2 to 4 °C; beyond that, a TECO chiller regulates to a tenth of a degree, from 150 to 6,000 L, and one version holds the water at 5 to 15 °C. In winter, the EHEIM thermo200 pond de-icer is designed for about 5 m² of pond, down to -20 °C outside. Thermometers, from suction-cup models to digital alarms, check the set temperature. For cold-water fish farming, read Salmoponics, cold-water aquaponics.








