Fluval E Electronic Aquarium Heater - 50W to 300W - 100W

The Fluval E Electronic Aquarium Heater is Fluval's electronic aquarium heater, sold from 50 to 300 watts, with a digital display on the body and a colour alert if the water drifts from the set point.

Key Features

• Dual-sensor VueTech microprocessor control, which takes two readings rather than one — a single failed sensor is how cheap heaters cook a tank
• Digital display on the heater itself showing the actual water temperature, not just the dial setting
• Colour-coded visual alert when the water moves away from the set temperature, so a problem is visible from across the room
• Four outputs: 50 W, 100 W, 200 W and 300 W
• Guard around the element so fish cannot rest against hot glass
• Made by Fluval, the aquatics brand of Rolf C. Hagen, which has been building aquarium filters since 1975

Choosing The Wattage

• The rough rule is 1 watt per litre in a normally heated room: 50 W for a tank up to about 50 L, 100 W to 100 L, 200 W to 200 L, 300 W to 300 L
• A cold room or a tank near a window needs more. A warm room needs less
• Two smaller heaters at opposite ends of a big tank is safer than one large one. If one sticks on, the other is not adding to it, and if one fails off you have not lost all heating
• Most tropical community fish want 24–26°C. Set it, then leave it alone — stability matters more than the exact number

Using It Safely

• Unplug anything electrical before putting your hands in the tank
• Switch a heater off and let it cool for fifteen minutes before lifting it out of the water. Hot glass in cold air can crack
• Fit a drip loop — let the cable hang below the socket so water runs off rather than down into it
• Put the heater where the filter flow passes over it. A heater in a dead corner heats that corner and nothing else
• Check the tank temperature with a separate thermometer. A heater's dial is a setting, not a measurement
• Heaters fail. They fail off, which is survivable, and they fail on, which is not. A thermometer you actually look at is the cheapest insurance in the hobby

Good To Know

• A heater is the piece of equipment most likely to kill a tank. The dual sensor and the visual alert are the reason to pay more for this one
• Let it sit in the tank for 20–30 minutes before switching on, so the glass reaches water temperature
• Always add dechlorinated water at roughly tank temperature during a water change. Cold water poured onto a hot heater is how they crack
• Fluval rates the E series for freshwater and saltwater