Aquaking Aqua Heater HE-300 watt aquarium heater

The AquaKing Aqua Heater HE-300 delivers 300 watts for a tank of 200 to 300 litres. That ratio is not marketing but arithmetic: heating water costs a fixed amount of energy, and the wattage decides how long you wait for it.

How long heating actually takes

Raising a 250 litre tank by five degrees takes roughly 1.45 kilowatt hours. At 300 watts that works out at a good four to five hours, and longer in practice, because the tank is losing heat to the room at the same time. Which is exactly why you choose a heater on how quickly it gets there rather than on what it eventually reaches: an undersized heater will hit the temperature, but it spends all night chasing it.

Think in watts per litre

This whole range works out at roughly one to two watts per litre. Below one watt per litre heating becomes slow and the heater will not hold temperature in a cold room. Above two watts per litre you gain little, because the thermostat mostly just cycles more often. For 200 to 300 litres, 300 watts sits neatly in that band.

What else makes a difference

A tank standing on a cold concrete floor loses most of its heat through the bottom. A sheet of insulation underneath does more than a bigger heater, and costs you once rather than every day. A lid helps too, since evaporation carries heat away with it.

Technical Specifications:

• Type: HE-300
• Power: 300 watts
• Suits: 200 to 300 litres
• Adjustable range: 22 to 34 °C, accuracy ±0.5 °C
• Build: plastic protective sleeve, fully submersible
• Dimensions: 32 x 34 x 400 mm
• Supply: 220 to 240 volts, 50 Hz

Frequently asked questions

How long will it take to heat my tank? Reckon on several hours for a few degrees, depending on the volume and how cold the room is.

Should I just buy a bigger heater? Little point. Above about two watts per litre the thermostat simply cycles more often for no gain.

Does it draw 300 watts continuously? No. It draws full power while heating, then only what is needed to hold the temperature.

Why will it not reach my set temperature? Usually because the tank is too large for the wattage, or the room removes heat faster than the heater adds it.