Fluval  M‑Series Submersible Heater

Maintain precise, stable temperatures in your aquarium with the Fluval M-Series Submersible Heater . Designed for both freshwater and planted setups, this fully submersible heater offers a mirrored finish, computer-calibrated thermostat, and a range of wattages to suit your tank size. Choose from five variants — M50 (50 W) , M100 (100 W) , M150 (150 W) , M200 (200 W) and M300 (300 W) — to match your aquarium volume and keep your fish, plants and shrimp healthy. Mirrored finish blends with aquarium aesthetics. Fully submersible design for flexible mounting. Computer-calibrated thermostat with adjustable dial. Range of wattages for tanks from ~50 L to ~300+ L. : Compact design with reliable European construction.

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Delivery in 2-5 Days

Fluval M-Series Submersible Heater – Premium Submersible Heating for Aquariums

The Fluval M-Series Submersible Heater offers advanced heating technology in a sleek design. Whether you’re maintaining a planted aquarium, community tank or reef-style setup, this heater series provides the reliability and precision you need. The mirrored aluminium/borosilicate finish helps it visually integrate into your aquascape, while the computer-calibrated thermostat ensures stable temperature control.

Specifications

Model	Power (W)	Recommended Tank Volume*
M50	50 W	Up to ~50 L (15 gal)
M100	100 W	Up to ~100 L (30 gal)
M150	150 W	Up to ~150 L (45 gal)
M200	200 W	Up to ~200 L (65 gal)
M300	300 W	Up to ~300 L (80 gal)

**Note:** Use at least ~1 W per ~1 L (or higher if tank sits in a cool room) as guideline, then select nearest model or higher for adequate safety margin.

Features & Benefits

Mirrored “reflective” finish — blends into aquascapes for less visual distraction.
Fully submersible — flexible mounting, better heat distribution.
Precision dial thermostat — set your preferred temperature easily.
Compact profile — fits behind decor or inside slim tanks.
Reliable build quality from Europe — trusted brand. How to Use the Fluval M-Series Heater

Select the model matching your aquarium size and expected temperature rise.
Mount the heater (using the suction cups) near water flow to ensure even heating.
Ensure the heater is fully submerged before powering on. Avoid dry-running.
Set the temperature dial to your target (e.g., 26-28 °C for tropical setups).
Monitor with an independent thermometer to validate actual water temperature.

Care & Maintenance Tips

Always unplug the heater before removing or working inside the aquarium.
Clean the heater glass occasionally to remove algae/mineral deposits improving efficiency.
Do not operate heater outside water or in very shallow water — risk of overheating.
Verify temperature accuracy periodically, as thermostats may drift after many years.
Keep spare heater available for large tanks as backup in case of failure.

Shipping

Delivery in 2-5 Days. Express delivery is available at checkout for an additional fee.

Returns

We accept returns within 3 days of delivery. Items must be unused and in their original packaging.

Enhance your aquarium with Fluval’s advanced filtration, lighting, and heating solutions. Experience powerful multi-stage filtration with Fluval 107, 207, 307, and 407 Performance Canister Filters. Create stunning aquascapes using Fluval Plant 3.0 and Marine 3.0 LED Lighting Systems. Maintain stable water conditions with Fluval E Series Electronic Heaters (E100, E200, E300) and M Series Submersible Heaters. Improve water clarity with Fluval FX4, FX6, and FX2 High-Performance Canister Filters, ideal for large aquariums. Trusted by aquarists worldwide, Fluval delivers innovation and reliability for every aquatic setup.