JBL ProTemp S 300 Heater with Heater Guard
Provides stable heating for aquariums with a volume between 160 and 400 liters (100 – 120 cm length).
Easy to install: insert the heater into the protective basket, set the desired temperature on the dial, immerse it in the aquarium, and secure it with suction cups to the inner aquarium glass.
Precise temperature control with a dial setting range of 20–34°C and accuracy of ±0.5°C. Features a star-shaped ceramic heating element for efficient and even heat distribution.
TÜV tested, watertight up to 100 cm. Includes unbreakable quartz safety glass with a protective screen and dry-running protection to prevent electrical hazards.
| Specification | Detail |
|---|---|
| Heating Power | 300 W |
| Temperature Range | 20 – 34 °C |
| Control Accuracy | ±0.5 °C |
| Cable Length | 195 cm |
| Guarantee | 2 years (extended to 4 years with product registration) |
FAQ
What is the temperature range of the JBL ProTemp S 300 heater?
The heater provides temperature control between 20°C and 34°C with an accuracy of ±0.5°C.
Is the heater safe for use in aquariums?
Yes, it is TÜV tested, has a dry-running protection feature, and includes unbreakable quartz safety glass with a protective screen for added safety.
How do I install the heater in my aquarium?
Insert the heater into the protective basket, set the desired temperature on the dial, immerse it in the aquarium, and attach it securely using suction cups to the inner glass panel.

Rebecca Bell –
The heater works steadily and maintains the ideal temperature in my 200-liter tank. The installation was simple and the suction cups hold well. I didn’t have any issues with overheating or temperature fluctuations.
John Churchill –
It keeps the water temperature consistent even during temperature drops. The ceramic element heats evenly and the safety glass feels solid. Only minor adjustment needed to set the temperature correctly at first.
Jack Dowd –
I’ve used it for over six months and it’s still functioning perfectly. The dry-running protection is a relief, and the temperature control is very precise. No leaks or damage observed.