Fluval M Series Premium Submersible Heater

A slim glass submersible heater with a mirrored outer finish that reflects the tank around it, so the equipment more or less vanishes into the aquascape.

Key features

• Reflective surface that blends into planted and rockwork tanks instead of standing out as a black tube
• Narrow glass body that tucks behind decor or into a back corner
• Adjustable thermostat dial, set once and then left alone
• Built in Europe, and a line with a long-standing reputation among aquarists for build quality
• Several wattages available for fresh and salt water — choose by tank volume

Glass heaters work well but they are breakable, so keep it fully submerged, unplug it before a water change and let it cool before you handle it. Position it in good flow so the thermostat reads real tank temperature, and keep a separate thermometer as a cross-check. Browse the rest in Fluval.