Buying guide
Submersible Heaters
Our pick
EHEIM thermocontrol+ e
Before you buy: The EHEIM thermocontrol+ e has a three-year warranty, while the Fluval E100 has a five-year warranty.56
The alternatives
Other contenders
For a 20 to 25 litre tank, choose the 25 W EHEIM thermocontrol e 25, which is rated for that size and includes dry-run protection.47
If you need a setting above 32 °C and its stated tank sizing suits your aquarium, the Fluval E100 reaches 34 °C.3
For a 30 to 80 litre aquarium on 230 V mains, consider the JBL PROTEMP S50 if you want an included heater guard and a dial on the unit. Check the difference between room temperature and your target water temperature when sizing it.91011
For big fish that knock things about
For a 30 to 80 litre tank on 230 V mains, choose the JBL PROTEMP S50 if you want an included guard around the heater.91011
For a tank with a low water line
For a 30 to 80 litre tank on 230 V mains, the JBL PROTEMP S50 can lie horizontally when a vertical heater is awkward to fit. Keep it immersed to the level required by its instructions.91011
For a tank kept cooler than tropical
Choose the EHEIM thermocontrol+ e when an 18 °C minimum setting suits your aquarium; a heater cannot cool water down to that setting.2
For a tank of 300 litres or more
For a 300 to 400 litre tank, consider the reviewed 200 W EHEIM thermocontrol+ e and check its sizing guidance for your installation.1
For a saltwater tank
For a 20 to 25 litre saltwater aquarium, choose the EHEIM thermocontrol e 25, which is rated for saltwater and that tank-size range.47
4 models / at a glance
Key differences
Compare the options
4 products
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Reset requirements4 models compared.
Highest setting (°C); higher is preferred · 0 to 34
Warranty (months); higher is preferred · 0 to 60
Compare models side by side
Choose two or three products to compare.
Models in this comparison
EHEIM thermocontrol+ e
- Warranty
- 36 months5
EHEIM thermocontrol e 25
- Warranty
- 36 months4
Fluval E100
- Warranty
- 60 months6
JBL PROTEMP S50
- Warranty
- 24 months9
Every specification for these products
| Specification | EHEIM thermocontrol+ e | EHEIM thermocontrol e 25 | Fluval E100 | JBL PROTEMP S50 |
|---|---|---|---|---|
| Wattage | 200 W1 | 25 W4 | 100 W3 | 50 W (Tested configuration: European 230 V / 50 Hz model)9 |
| Largest tank it heats | 400 l1 | 25 l7 | ≈114 l (30 gallons)3 | 80 l10 |
| Smallest tank it suits | Not published | 20 l7 | Not published | 30 l11 |
| Temperature accuracy | Not published | Not published | Not published | 0.5 °C11 |
| Tube material | Glass5 | Glass8 | Glass6 | Quartz glass9 |
| Shuts down out of water | Not published | Yes4 | Not published | Yes9 |
| Overheat cut-out | Not published | Not published | Not published | Not published |
| Highest setting | 32 °C2 | 32 °C4 | 34 °C3 | 34 °C11 |
| Lowest setting | 18 °C2 | 20 °C4 | 20 °C3 | 20 °C11 |
| Warranty | 36 months5 | 36 months4 | 60 months6 | 24 months9 |
| Guard included | Not published | Not published | Not published | Yes9 |
| Can lie flat | Not published | Not published | Not published | Yes9 |
Find the right fit
4 products
How they compare
Scroll the table to see every product and specification.
| Specification | Our pickEHEIM thermocontrol+ e | EHEIM thermocontrol e 25 | Fluval E100 | JBL PROTEMP S50 |
|---|---|---|---|---|
| Wattage | 200 W1 | 25 W4 | 100 W3 | 50 W (Tested configuration: European 230 V / 50 Hz model)9 |
| Largest tank it heats | 400 l1 | 25 l7 | ≈114 l (30 gallons)3 | 80 l10 |
| Smallest tank it suits | Not published | 20 l7 | Not published | 30 l11 |
| Temperature accuracy | Not published | Not published | Not published | 0.5 °C11 |
| Tube material | Glass5 | Glass8 | Glass6 | Quartz glass9 |
| Shuts down out of water | Not published | Yes4 | Not published | Yes9 |
| Overheat cut-out | Not published | Not published | Not published | Not published |
| Highest setting | 32 °C2 | 32 °C4 | 34 °C3 | 34 °C11 |
| Lowest setting | 18 °C2 | 20 °C4 | 20 °C3 | 20 °C11 |
| Warranty | 36 months5 | 36 months4 | 60 months6 | 24 months9 |
| Guard included | Not published | Not published | Not published | Yes9 |
| Can lie flat | Not published | Not published | Not published | Yes9 |