Aquarium UV steriliser, 5 to 36 W

Name: Aquarium UV steriliser, 5 to 36 W
Brand: JBL
SKU: 6039400
Availability: InStock

¥19,300

This UV-C steriliser is installed inline on the filter return and treats green water and suspended pathogens, in both fresh and salt water. Its four power ratings cover 300 to 3,000 litres, each with its own maximum pump flow rate, and the lamp cuts out automatically when the housing is opened.

Power : 5 w

5 W

11 W

18 W

36 W

7/7 customer service by e-mail

Payment in instalments, free of charge

The summary

What you receive: the unit with its lamp fitted, its connectors, and its instruction manual.
The key figure: the maximum pump flow rate, from 300 to 1,000 L/h depending on the power.
Volume treated: 300 to 3,000 L for disinfection, 100 to 800 L against green water.
Daily effort required: none, except replacing the lamp once a year.
Space needed: a straight run of 32 to 61 cm depending on the model, outside the tank.
Built-in safety: the lamp cuts out automatically as soon as the housing is opened.

A green water treatment unit fitted inline on the filter return

Greenish water cannot be fixed by water changes or by a filter alone. The algae responsible are unicellular, they float freely and pass straight through any foam media. A UV-C steriliser treats them where they live, suspended in the water as it flows through. The unit is installed in-line on the return pipe from the external filter; the water passes alongside a lamp sealed inside a quartz tube, receives the radiation, and returns to the tank. Nothing dissolves, nothing is dosed, and there is no product to add to your water. That is the fundamental difference from a chemical treatment, which works once and then allows the problem to return, whereas an in-line unit keeps working for as long as it runs.

💡 What the UV-C reaches

UV radiation acts on the DNA of micro-organisms that pass in front of the lamp, whether single-celled algae, free-floating bacteria or parasites at their free-swimming stage. It has no effect on anything that doesn't pass in front of it. The bacteria colonising the media in your filter stay exactly where they are and continue converting ammonia, because they are fixed in place rather than carried through the water. A UV steriliser therefore does not disrupt an established nitrogen cycle, and our article on the nitrogen cycle explains why the distinction comes down to the substrate.

🚰 The flow rate

Flow rate is the figure everyone skips, yet it determines the outcome. The faster water moves past the lamp, the less radiation it receives. Each wattage therefore has a maximum pump flow rate, which varies depending on what you want to achieve: the 18 W unit treats a 1,500 L tank with partial disinfection at 400 L/h, but only 500 L against green water, at 500 L/h. If your filter delivers more than the stated value, move up to the next power level or install the unit on a slower bypass. A Y-fitting and a regulating valve are all you need to create this bypass, and it is often cheaper than changing the model.

You're aiming for green water

The treated volume drops sharply. A 500-litre tank already requires the 18 W unit, and an 800-litre tank the 36 W.

You're aiming for sprouts

The same unit covers three times the volume. The 18 W handles 1,500 litres; the 36 W handles 3,000.

Three ways to render it ineffective

Connecting it to a pump faster than the model's maximum flow rate cancels out most of the treatment, with no indication that this is happening. Running it with a lamp that is over a year old amounts to the same thing, since the lamp still illuminates without sterilising any longer. And switching it on before the circulation has been started causes the lamp to heat up in still water, which damages the quartz sleeve.

The replacement lamp should be planned for

Note the date of commissioning on the unit and order the replacement lamp before the end of the first year, as it is the only consumable in the device and replacing it in good time determines everything else. Also keep a phosphate test to hand if your water turns green again despite the unit, as a UV lamp treats the symptom when it is the algae's nutrient supply that is sustaining the problem.

🔒 Lamp safety and service life

A magnetic switch cuts the lamp as soon as the housing is opened, preventing any exposure of the eyes to the radiation. The body has a double glass wall and is UV-resistant. The key point to bear in mind going forward is different, because a UV-C lamp loses its germicidal power well before it stops working. It will still glow, blue, but it will no longer sterilise. This is why it should be replaced on a schedule, once a year, and not when it finally gives out. Use this replacement as an opportunity to clean the quartz tube, whose limescale film blocks a proportion of the radiation long before the lamp reaches the end of its life. A simple wipe with diluted white vinegar, followed by a thorough rinse, is enough to restore its transparency, and this can be done at the same time as cleaning the filter to avoid an extra handling step.

🐟 Aquarium, pond and planted circuit

The two higher-wattage units carry flow ratings published for pond use, considerably higher than for aquariums because water circulates differently in a pond, the 18 W model covering 15,000 L for disinfection and 4,000 L against green water, and the 36 W reaching 30,000 L and 8,000 L respectively, in both cases with a pump of up to 4,000 L/h. In a system where fish and plants share the same water, fit it on a secondary loop rather than on the main return, so that you clarify the water without reducing the flow feeding your growing beds. For algae growing on surfaces rather than in the water column, the unit will have no effect, our article on pond algae in summer covers the approaches that actually work.

📦 What the box contains

The box contains the unit fully assembled with its lamp fitted, its connection fittings, and its instruction manual. The cable is 2 m long on the 11 W model and 5 m on the 18 and 36 W models, and the unit requires a straight run of 32 to 61 cm depending on the model in order to fit inside the cabinet. Measure this length before ordering, as a more powerful model is chosen on flow rate but installed according to the available space, and these two constraints do not always align in an aquarium cabinet already occupied by an external filter.

🔁 When to run it

A UV steriliser does not necessarily need to run all year round. To clear an established green water bloom, run it continuously until the water clears, this generally takes 3 to 7 days, then switch it off until the next outbreak. As a preventive measure on a pond exposed to full sun, run it throughout the warmer months and switch it off in winter. In an aquarium, many hobbyists run it for a few hours a day on a timer socket, which is enough to keep the water clear while sparing the lamp. The key point is that hours logged count towards its service life, and running a unit unnecessarily wastes its only consumable for nothing. A timer socket costs just a few pounds and almost doubles the useful life of a lamp in a tank where the water stays clear on its own most of the time.

Technical specifications

The essentials

Device type: In-line UV-C steriliserSits on the filter return pipe, outside the tank.
Power ratings: 5, 11, 18 and 36 WLamp wattage, which determines the volume treated.
Accepted water types: Fresh and marineThe two higher-output models also cover larger pond volumes.
Safety: Magnetic cut-off on openingThe lamp switches off before the housing opens.

Volume treated and maximum flow rate

5 W: 300 L, or 100 LPartial disinfection followed by green water, pump at 300 L/h maximum.
11 W: 800 L, or 200 LPartial disinfection followed by green water, pump at 500 L/h maximum.
18 W: 1,500 L, or 500 L400 L/h pump for disinfection, 500 L/h against green water.
36 W: 3,000 L, or 800 LThe only model that accepts a 1,000 L/h pump.

Connections, lamp, and footprint

Pipe end caps: 16 to 19 mm, or 12 to 40 mmThe narrow range applies to the 11 W model, the wide range to the 18 and 36 W.
Minimum straight length: 32, 42 or 61 cmThe dimension that most often prevents fitting beneath an aquarium.
Lamp cap: G23 or 2G11G23 on the 11 W, 2G11 on the 18 and 36 W.
Cable length: 2 or 5 m2 m on the 11 W, 5 m on the 18 and 36 W.
Lamp lifespan: Approximately 8,000 hoursThe germicidal output drops before the lamp actually fails.
References: 6047100, 6047200, 6047300In order of wattage: 11, 18, and 36 W.

To budget for separately

Replacement lamp: 1 tube at the base of the unit, every year
Water circulation: A filter whose flow rate stays within the limit

8 further specifications are available in the detailed view.

In the box

1 assembled steriliser, complete with its UV-C lamp and quartz sleeve
1 set of connection fittings to be cut to the pipe diameter
1 power cable permanently attached to the unit
1 installation guide

Treated volumes, maximum pump flow rates, bases and lengths recorded on 20/09/2026 from the supplier's technical data sheets.

Steriliser for an aquarium or pond clarifier?

The same UV-C treatment, across two circuits that share neither the same flow rate nor the same pipes.

Do you need an aquarium unit or a pond unit? One is sized according to your pump's flow rate, the other according to your pond's stocking level.

	Maximum lamp wattage (W)	Minimum lamp wattage (W)	Several power outputs available	Designed for the garden pond	Designed for the aquarium	Sizing guided by the stocking level	Price
Pond UV steriliser, 7 to 60 WYour choice	60 W	7 W	7	Yes	No	Yes	¥10,900
Recommended Aquarium UV steriliser, 5 to 36 WYour choice	36 W	5 W	4	Yes	Yes	No	¥19,300

Pond UV steriliser, 7 to 60 W

Power output

Maximum lamp wattage (W)60 W

Minimum lamp wattage (W)7 W

Several power outputs available7

Intended use

Designed for the garden pondYes

Designed for the aquariumNo

Sizing guided by the stocking levelYes

Aquarium UV steriliser, 5 to 36 WRecommended

Power output

Maximum lamp wattage (W)36 W

Minimum lamp wattage (W)5 W

Several power outputs available4

Intended use

Designed for the garden pondYes

Designed for the aquariumYes

Sizing guided by the stocking levelNo

Lamp wattages, treated volumes and applications recorded on 20/09/2026 from the technical data sheets of both suppliers.

Estimate your
delivery time

Long and fragile parcel, protected for the quartz tube. Delivered to your door or to a collection point, your choice at checkout. The exact amount depends on the option selected.

Frequently asked questions

10 questions

6 key questions, 10 in the detailed view

Why are there two different volumes for the same unit?

A steriliser does not perform the same work depending on the dose of radiation delivered. Reducing bacteria requires less energy than destroying algae, so the same unit covers a large volume in the first case and a small one in the second.

Wattage	Partial disinfection	Against green water
5 W	300 L	100 L
11 W	800 L	200 L
18 W	1 500 L	500 L
36 W	3 000 L	800 L

Read the column that corresponds to the problem you are trying to solve.

My filter delivers 900 litres per hour — which model should I choose?

Does it kill the bacteria in my filter?

When should the lamp be replaced?

Where does the unit fit into the circuit?

What pipe diameter does it accept?

How much space needs to be allowed inside the unit?

Is it suitable for seawater?

Can it treat a garden pond?

The two higher-wattage models carry published figures for pond use, and these are considerably higher than for aquarium use.

The 18 W model covers 15,000 L for partial disinfection and 4,000 L against green water. The 36 W goes up to 30,000 L and 8,000 L. In both cases, the pump must not exceed 4,000 L/h.

The 5 W and 11 W models have no published pond figures and remain aquarium units. If you need something for a pond, consider a clarifier designed for outdoor use, whose housing and fittings are sized accordingly.

Where should it be placed in an aquaponic circuit?

Place it on a secondary loop, never on the return line feeding the growing beds. This way you maintain the flow rate your plants need whilst clarifying part of the volume. The nitrogen cycle is not at risk, since the bacteria that drive it live fixed within the filter media rather than in suspension. To understand what actually causes cloudiness in a recirculating system, see our article on cloudy water in aquaponics.

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Aquarium UV steriliser, 5 to 36 W

The summary