The Eheim reeflexUV UV Steriliser is designed to improve water clarity and reduce free-floating microorganisms in both freshwater and marine aquariums. Unlike many conventional UV sterilisers that force water through bends or indirect flow paths, reeflexUV uses a straight-through water path with a high-gloss internal aluminium reflector, helping increase UV-C exposure and improve efficiency.
The unit is especially useful for reducing green water, bacterial cloudiness, free-floating algae spores, harmful bacteria and infectious parasite stages that pass through the steriliser. Beneficial bacteria living in your filter media and substrate are largely unaffected because the UV only acts on organisms suspended in the water column. Eheim rates the reeflexUV range for aquariums from 80L right through to 2000L.
Models & Specifications
| Model |
Recommended Aquarium Size |
UV-C Power |
Max Flow for Germ Reduction |
Max Flow for Water Clarification |
Approx. Dimensions |
| reeflexUV 350 |
80–350L |
7W |
200 LPH |
400 LPH |
350 × 115 × 130mm |
| reeflexUV 500 |
300–500L |
9W |
400 LPH |
800 LPH |
380 × 115 × 130mm |
| reeflexUV 800 |
400–800L |
11W |
600 LPH |
1200 LPH |
470 × 115 × 130mm |
| reeflexUV 1500 |
700–1500L |
18W |
1000 LPH |
2000 LPH |
500 × 115 × 130mm |
| reeflexUV 2000 |
1200–2000L |
24W |
1500 LPH |
3000 LPH |
560 × 115 × 130mm |
The lower flow figure is Eheim's recommended maximum when targeting harmful bacteria and infectious parasite stages. The higher flow figure is the recommended maximum when using the unit primarily to remove green water or bacterial turbidity.
Key Features
✔ Suitable for freshwater and saltwater aquariums
✔ Helps reduce harmful free-floating bacteria
✔ Helps reduce infectious parasite stages passing through the unit
✔ Highly effective for green water and bacterial cloudiness
✔ Helps control free-floating algae spores
✔ High-gloss internal aluminium reflector increases UV-C exposure
✔ Straight-through water path helps minimise flow restriction
✔ Eheim states the reflector design can provide up to 1.8× the effectiveness of conventional UV sterilisers
✔ Does not remove beneficial bacteria established in filter media or substrate
✔ AUTO-OFF safety system switches the UV lamp off when the unit is opened
✔ Can be installed in different orientations and flow directions
✔ Includes mounting bracket, ballast/power cable and hose connections
✔ Maximum operating pressure: 0.8 bar
✔ 3-year Eheim manufacturer warranty
How reeflexUV Works
Aquarium water is passed through the steriliser and exposed to UV-C light. The UV radiation acts on free-floating microorganisms passing through the unit, including algae spores, bacteria and infectious parasite stages.
Eheim's design uses a reflective aluminium interior so UV-C radiation is reflected back through the passing water from multiple directions. The water also follows a direct path through the chamber rather than being repeatedly redirected, helping maintain efficient flow through the unit.
Germ Reduction vs Water Clarification
Flow rate is especially important with UV sterilisation because slower water movement increases the amount of time organisms are exposed to UV-C light.
For reducing harmful bacteria and infectious parasite stages, use the lower maximum flow recommendation.
For green water, algae spores and bacterial cloudiness, the reeflexUV can be operated at the higher clarification flow rate listed for each model.
Hose Connections
The reeflexUV range is designed for inline installation into an aquarium filtration system and supports common Eheim hose sizes including:
✔ 12/16mm
✔ 16/22mm
The unit requires water flow from an external filter or suitable pump and is designed to work alongside your normal aquarium filtration rather than replace it.
UV Lamp Maintenance
The UV-C lamp gradually loses effective output with use even if it continues to illuminate. Eheim specifies a maximum operating life of approximately 8,000 hours, which is roughly one year of continuous operation, after which the lamp should be replaced to maintain effective UV performance.
Eheim also recommends cleaning the internal glass tube regularly, ideally when servicing your filter and at least approximately every three months.
Perfect For
✔ Freshwater aquariums
✔ Marine and saltwater aquariums
✔ Large display aquariums
✔ Fish rooms and breeding systems
✔ Reducing green water
✔ Clearing bacterial cloudiness
✔ Reducing free-floating algae spores
✔ Supporting disease-management and biosecurity practices
✔ Aquariums running external canister filters or sump systems
✔ Systems where improved water clarity is a priority
Important Information
A UV steriliser should be used as additional water-treatment equipment alongside proper mechanical and biological filtration. It does not replace regular filter maintenance, water changes or appropriate aquarium husbandry.
