Aquael Flow Heater 2.0 or BT external heater, 50 to 500 W
Regular price
104,90 €
Regular price
Sale price
104,90 €
Unit price
/
per
34,96 € × 3 with no fees
Klarna.
Aquael Flow Heater heaters are fitted in line on the return pipe of an external filter, outside the aquarium. The BT version can be set to a tenth of a degree from your phone, from 50 to 500 W; the 2.0 version shows the temperature on its screen and comes in 300 or 500 W.
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The summary
- Which version: the BT is controlled from your phone, the 2.0 is set on the unit itself.
- Which power: adjustable from 50 to 500 W on the BT, 300 or 500 W on the 2.0.
- Installing it: on the return pipe of an external filter, in 16/22 or 19/25 mm.
- Its safety: automatic cut-off in the event of overheating or when the flow stops.
A heater that sits on the filter pipe, with a display or Bluetooth control
The Aquael Flow Heater heaters warm the water in your aquarium from outside the tank. They fit onto the return pipe of an external filter and come in two versions. The BT version is set from your phone via Bluetooth, from 19 to 33 °C in tenths of a degree, with a maximum power that can be adjusted from 50 to 500 W. The 2.0 version is set directly on the unit, shows the temperature on its screen and comes in 300 or 500 W.
🔌 A heater on the pipe
These heaters are not placed in the water: they fit onto the pipe through which the external filter returns filtered water to the tank. The water is warmed as it passes through the body of the unit, then the filter's current distributes it throughout the whole volume, so the heat arrives already mixed rather than lingering around a tube. There is therefore no heating element in your décor, and your fish can neither press against it nor knock it over. Electronic sensors monitor the temperature continuously, five on the BT version and three on the 2.0 version, and the unit switches off the heating by itself in the event of overheating or if circulation stops. Both versions can be used in freshwater and in seawater.
External filter
Both versions connect to its return pipe, in 16/22 or 19/25 mm.
Large aquarium
The 500 W of the 2.0 version and the BT's top model heat up to 1,000 litres.
Saltwater
Both versions heat a marine tank as well as a freshwater aquarium.
Day and night cycle
The BT version lowers the temperature in the evening, as in a natural environment.
An Aquael external filter with the same pipe diameters
If your tank does not yet have an external filter, the Aquael Ultramax 1000 or 2000 external filter connects with 16/22 or 19/25 mm fittings, exactly the two diameters that the heater's fittings accept. You then insert the Flow Heater on its return pipe, under the cabinet, without an adaptor. The basket tank provides the biological filtration while the heater maintains the temperature on the same circuit.
Restart the filter after every maintenance session
The heater only works if water flows through it, and it stops as soon as the filter stops. When you switch the filter off to clean its baskets, the tank therefore stops being heated until it is restarted. Always switch the filter back on at the end of maintenance, then check on the display or in the app that heating has resumed. If the 2.0 version has gone into safety mode, which is shown by the 20 and 33 °C indicator lights flashing together, unplug it, let it cool down and then plug it back in, as it does not restart by itself.
🖥️ The 2.0 version with a display
The Flow Heater 2.0 suits those who prefer to adjust settings on the unit itself, without a phone. Its LED display shows the water temperature and the set temperature at the same time, and a single button lets you choose that setting between 20 and 33 °C. The electronic thermostat holds it to within 0.5 °C, while the intelligent heating system adapts the power delivered to the volume of the tank to avoid sudden swings. The 300 W model suits an aquarium of 100 to 600 litres, the 500 W one a tank of 300 to 1,000 litres. Between 300 and 600 litres, either will do: choose the 500 W if the tank is in a room that is cool in winter.
📱 The BT version and its app
The BT version is set up in the free AQUAEL BT app, for iOS and Android. In it you set the desired temperature, from 19 to 33 °C with a precision of 0.1 °C, then choose between two modes. In constant mode, the water stays at the same value day and night. In day and night mode, you enter a day temperature, a night temperature and the sunrise and sunset times, and the transition from one value to the other is spread over 15 to 180 minutes. This gradual change reproduces the slight nighttime drop of a natural environment without any sudden swing for your fish. A PIN code protects the settings.
Its maximum power can also be set in the app, from 50 to 500 W in steps of 50 W, which lets the same unit suit a small tank or a 1,000-litre aquarium. The app constantly displays the water temperature, keeps a 7-day history of heating periods and alerts you when the water drifts 2 °C away from the set point. If the history shows very long heating periods, going up one step will help. Bluetooth requires your phone to stay nearby; the Aquael WiFi Gateway BT, sold separately, lets you monitor the unit when you are away from home.
🔧 Fitting it to the circuit
Choose an accessible spot on the filter's outlet pipe, usually inside the cabinet, cut the pipe and insert the heater between the two ends using the fittings, in 16/22 or 19/25 mm depending on your filter, following the direction of the arrow moulded into the housing. The unit is then mounted always vertically, using its suction-cup brackets or screwed to the cabinet wall, never above the water surface. On a 16/22 mm pipe, a double quick-connect tap lets you shut off the line and remove the filter without emptying the circuit, while the heater stays in place. Before switching on, check that water is flowing through the body of the unit: it only heats under that condition.
🌱 In aquaponics
In an indoor aquaponics system, the water temperature governs the fishes' appetite, the activity of the nitrifying bacteria and, as a result, the amount of nitrate available to the plants. Tropical species such as tilapia need warm water all year round, and a Flow Heater keeps it that way with no visible element in the fish tank. You fit it on the delivery pipe of the pump that returns water to the fish, provided that pipe is 16/22 or 19/25 mm. The bacteria of the nitrogen cycle slow down in cold water, so a stable temperature keeps them active through the winter.
Even so, keep an independent thermometer in the tank, opposite the water return: it confirms the device's reading and tells you straight away if circulation stops. In winter, a lid on the tank and insulation on the walls reduce heat loss. In spring, simply lowering the set temperature is enough to follow the room temperature.
Technical specifications
Connected Bluetooth version
- Maximum power
- 50 to 500 W, in steps of 50 WFor aquariums up to 1,000 L
- Adjustment
- 19 to 33 °C, in 0.1 °C steps
- Order
- AQUAEL BT app, via BluetoothiOS and Android, PIN code available
- Alert
- Deviation of 2 °C from the set point
Version 2.0 with display
- Power
- 300 or 500 W
- Recommended volume
- 100 to 600 L or 300 to 1,000 LThe 500 W for a large tank or a cool room
- Adjustment
- 20 to 33 °C, accurate to 0.5 °C
- Display
- LED display, temperature and setpoint
Both versions
- Pipes
- 16/22 or 19/25 mm
- Safety features
- Overheating, flow cut-offOn the 2.0, unplug it and let it cool down to restart it
To budget for separately
- Circulation
- An external filter or a pump
- Remote control of the BT
- WiFi Gateway BT bridgeOptional, out of Bluetooth range
4 further specifications are available in the detailed view.
In the box
- 1 Aquael Flow Heater, BT or 2.0 version depending on the variant chosen
- Fittings for 16/22 and 19/25 mm pipes
- Suction cup mounting brackets, in both versions
Power ratings, adjustment ranges, accuracy, volumes, functions and safety features recorded on 11/10/2026 from the Aquael product pages and information sheets for both versions. 2-year warranty.
Which Flow Heater for your tank?
One version controlled from your phone, one version with a display, each in two power ratings.
Which version?
Two answers, and the table highlights the heater that suits you.
| Maximum power (W) | Recommended volume | Adjustment | Control | Day and night mode | Price | |
|---|---|---|---|---|---|---|
| Recommended BT connectedYour choice | 500 W | Up to 1,000 L | 19 to 33 °C, to 0.1 °C | Bluetooth app | Yes | 104,90 € |
| 2.0, 300 WYour choice | 300 W | 100 to 600 L | 20 to 33 °C, accurate to 0.5 °C | Screen and button | No | 59,90 € |
| 2.0, 500 WYour choice | 500 W | 300 to 1,000 L | 20 to 33 °C, accurate to 0.5 °C | Screen and button | No | 74,90 € |
BT connectedRecommended
Adjustment and power
Maximum power (W)500 W
Recommended volumeUp to 1,000 L
Adjustment19 to 33 °C, to 0.1 °C
ControlBluetooth app
Day and night modeYes
2.0, 300 W
Adjustment and power
Maximum power (W)300 W
Recommended volume100 to 600 L
Adjustment20 to 33 °C, accurate to 0.5 °C
ControlScreen and button
Day and night modeNo
2.0, 500 W
Adjustment and power
Maximum power (W)500 W
Recommended volume300 to 1,000 L
Adjustment20 to 33 °C, accurate to 0.5 °C
ControlScreen and button
Day and night modeNo
Power ratings, volumes and adjustment ranges recorded on 11/10/2026 from the Aquael product pages.
Help choosing
Two questions about your tank
Documents & manuals
Instructions for the Flow Heater BT
Multilingual instructions including French: vertical fitting on the outlet pipe, direction of the arrow, indicator lights and modes of the AQUAEL BT app.
Flow Heater 2.0 instruction manual
Multilingual instructions including French: fitting the 16/22 and 19/25 mm fittings, dial adjustment, reading the indicator lights and safety mode.
Document not showing? Some publishers block display inside a frame, so open it in a tab.
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Frequently asked questions
10 questions
6 key questions, 10 in the detailed view
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