JBL PROTEMP External Aquarium Heater

The JBL PROTEMP external aquarium heater is designed to fit into an external filter’s water-return hose rather than sit inside the aquarium. Its digital display shows current and target temperatures, while the listing describes automatic temperature regulation and protection against overheating and dry running.

At a glance

Fits into the water-return hose of an external filter. The listing says it cannot be used with internal filters.
Digital LED display shows current and target temperatures side by side, with SET and arrow keys for adjustment.
Listing claims automatic control from 20-35 °C and safety shut-off for overheating or dry running.
Six adapters are listed for hose sizes 12/16, 16/22 and 19/25 mm.

Price

£72.05Save 24%

Reference price: ~~£94.90~~

Price checked: 14 Nov 2026

View offer

Pros and cons

Pros

External-hose installation keeps the heater outside the aquarium, if the setup uses a compatible external filter.
Side-by-side current and target temperature readings make the set point and displayed water temperature easy to compare.
Dry-running and overheating shut-off are listed safeguards, including in the described filter-cleaning scenario.

Cons

It is not suitable for aquariums using an internal filter, according to the product description.
The heater and its connections require space in the filter return hose, and the listing says the hoses must not be kinked.

Technical specifications

11 specifications

Identity
Brand	JBL
Model	PROTEMP

Dimensions and installation
Weight listed	908 Grams
Listed aquarium capacity	External heater for aquariums from 10 to 600 litres
Hose sizes	12/16, 16/22, 19/25 mm
Total length including hose connections	35 cm
Additional hose length	2 x 2 cm

Temperature and operation
Adjustable temperature range	20-35 °C

Other details
Manufacturer	JBL GmbH & Co. KG
Country of origin	China
Warranty listed	2 year manufacturer

What to know before buying

The 10 to 600 litre range is a listing claim. Suitability for a particular aquarium will depend on its setup and conditions. The described installation requires an external filter return hose, and the hoses must not be kinked. The listing also gives a total length of 35 cm including connections, plus 2 x 2 cm for the hoses.

What’s in the box

Included

External heater with ceramic heating element
6 adapters
Cleaning brush

Who is it for?

A good fit for

Aquarium keepers with an external filter and a return hose matching one of the listed adapter sizes.
Buyers who want an external heater with a digital readout of current and target temperatures.

Less suited to

Aquariums that use an internal filter or have no compatible external-filter return hose.
Setups without room for the heater and its hose connections.

JBL PROTEMP External Aquarium Heater · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.6 / 5 · 6 ratings

5 stars79%79%
4 stars0%0%
3 stars21%21%
2 stars0%0%
1 star0%0%

Aggregate ratings lean positive, but the small number of ratings and a notable three-star share leave room for varied experiences. With no written feedback supplied, they do not reveal what customers liked or disliked. Treat the ratings as limited context rather than evidence of heating performance or suitability for a particular filter setup.