Our houses aren’t the only things to need heating. Our fish habitats, or aquariums, also need to be kept at a constant, feel-good temperature. This can vary from aquarium to aquarium and needs to be individually regulated.
Underfloor heating, as we know it in our houses, doesn’t heat the water in the aquarium. There it’s used to circulate the nutrients in the substrate and to prevent patches of rot forming (more on this in this guide: Substrate heater ).
Heating in the aquarium
But how is the water in the aquarium actually heated and kept constant? The old standards for this are the so-called heating rods. They are simply hung in the aquarium, measure the temperature and regulate the heating interval up to the desired target value. This is why they can also be found under the term heater or heating thermostat. With the JBL PROTEMP S 100 (available in six sizes), JBL also offers a safety heater thermostat with a protective basket which protects your fish from burns and from accidents caused by shocks and injuries at its glass body. Anyone who was paying attention in Physics or who asks an electrician, will know that 230 V in water is unusual. Thanks to the integrated safety technology and the protective basket, it’s no problem with JBL heaters and has been standard for years. It’s safe for you, the user, as it is for your fish.
In addition to these conventional heating rods there are now also all-plastic body heaters from other manufacturers on the market. Some have abandoned flexibility in favour of a fixed preset target temperature.
But what bothers so many aquarists about a heater inside the aquarium?
It is simply a matter of appearance. This additional component in the aquarium is difficult to hide and can get covered with algae or even clogged with lime, thus restricting the heater's performance, and has few benefits apart from its function. Of course, it is quick and easy to remove and re-integrate, if necessary.
If you follow the trends towards nature aquariums and aquascapes, you will notice that actually all technical components or accessories are almost disappearing from the aquarium optically.
When JBL launched an external heater, often referred to as a flow heater or inline heater, just under a year ago, the demand was enormous.
The external heater for the perfect aquarium
This invisible heating, which saves space in the aquarium and removes a live part from the aquarium, has proved appealing to lots of aquarists. Water comes from the external filter and is carried through the heater. You are probably familiar with instantaneous water heaters which heat water in a bathroom. Mechanical damage to the heater caused by knocks or falls are prevented thanks to the JBL PROTEMP e300 (also available as JBL PROTEMP e500 ), and the heater also monitors the temperature and issues warnings when the target value is exceeded, thus protecting your fish. Just like the JBL Safety heater thermostats with protection basket, the external heaters are suitable for freshwater and marine water.
At only 30.5 cm long, the unit can be installed effortlessly in any aquarium cabinet. The aquarium looks tidier and the layout is more attractive.
Both external heaters can be connected with the standard hose sizes 12/16, 16/22 and 19/25 mm and are available for aquariums from 80-600 litres.
What if you do not have an external filter and still want to switch to an external heater? You can connect the external heater via a small submersible pump such as the JBL ProFlow t300 (see Pumps for other models) and operate it in your aquarium, even if it has an internal filter.
Finally, we would like to say a word about its efficiency. Both types of heating are efficient and work quickly and reliably. The heater rod, which is 100% under water, has a slightly higher efficiency than a flow heater. This is because the heat can only escape into the water. With flow heaters, the heating is directed and is absorbed very efficiently by the water, so the difference is hardly noticeable.
