Fluval UVC In-Line Clarifier


UVC In-Line Clarifier  – Quickly and easily connected to most canister filter setups, the UVC In-Line Clarifier eliminates suspended bacteria and algae for a clear and healthy aquarium. 


UVC In-Line Clarifier  – Quickly and easily connected to most canister filter setups, the UVC In-Line Clarifier eliminates suspended bacteria and algae for a clear and healthy aquarium. 


  • A chemical-free and maintenance-free way to purify water
  • Eradicates suspended bacteria and algae in the water column that contribute to cloudy and green water, respectively
  • Helps prevent the growth of cyanobacteria that often smothers and destroys aquatic plants
  • Does not harm beneficial, surface-dwelling bacteria
  • Condensed design redirects water flow up, down and around the bulb to maximize contact time for effective clarification
  • CCFL (Cold Cathode Fluorescent Light) technology runs cooler than traditional UVC bulbs to last up to 30,000 hours (3X longer)
  • Easily fits within aquarium cabinetry without cluttering existing filtration setup
  • Quickly connects in-line to all canister filter hosing with an internal diameter of 5/8” (or 16mm), including all Fluval 07 and 06 Series filters
  • Multi-directional – works in either direction so there is no need to move existing filter setup
  • Energy-efficient – up to 80% less expensive to operate than competitive clarifiers
  • 4–24 hour timer included for optional intermittent use
  • Hose connector and mounting hardware included – no additional parts required
  • For use in freshwater, saltwater and even turtle aquariums where algae is often present
  • 2 YEAR LIMITED WARRANTY. For registration please visit: fluvalaquatics.com/warranty
  • The Fluval UVC in-line Clarifier is guaranteed for defective parts and workmanship for a period of 2 years from the date of purchase. This guarantee is valid with proof of purchase only. The guarantee is limited to repair or replacement only and does not cover consequential loss, loss or damage to livestock and personal property or damage to animate or objects, irrespective of the cause thereof. This guarantee is valid only under normal operating conditions for which the unit is intended. It excludes any damage caused by unreasonable use, negligence, improper installation, tampering, abuse or commercial use. The warranty does not cover wear and tear, breakage of glass or parts which have not been adequately or correctly maintained. WARRANTY IS ONLY VALID WITH PROOF OF PURCHASE FROM AN AUTHORIZED FLUVAL DEALER. WARRANTY DOES NOT AFFECT YOUR STATUTORY RIGHTS.
  • For use in freshwater and saltwater aquariums
  • Instruction manual for more reference.
  • Package contents:
    1. 3W UVC In-Line Clarifier unit
    2. 18.5″ / 47 cm Ribbed hosing
    3. 4-24 Hour timer
    4. 100-240V / 24V Power supply
    5. 2 Mounting screws


My aquarium is cloudy and smells bad. Will the UVC clarifier help?

If the cloudiness is due to suspended bacteria or algae, the UVC clarifier will indeed clear the water, provided it is installed as instructed. To help reduce smells, the best solution is the use of activated carbon. It is also advisable to investigate the source of the odor: if it is due to decomposing organic matter make sure to remove it and perform a regular partial water changes.

Does the UVC clarifier prevent algae growth on surfaces within the aquarium?

The UVC clarifier will only neutralize suspended bacteria and algae, and as such will not prevent the growth of most algae on the aquarium glass, gravel, décor, etc. Some surface-dwelling algae species exist as spores at some life stages, however: the UVC clarifier will help prevent the growth of these species.

Will using the UVC clarifier harm the beneficial bacteria in my aquarium?

The beneficial species of heterotrophic and nitrifying bacteria in an aquarium live on surfaces in the filter, in the substrate, on plants, etc. They do not live in the water column and as such are entirely unnaffected by UVC sterilization.

Will the UVC clarifier have any negative effects on the beneficial microorganisms in my reef aquarium?

The UVC clarifier may affect some beneficial microorganisms present in the water column, including ones that may be a food source for some species of fish and coral. In healthy reef aquariums, however, these microorganisms are very abundant and the UVC clarifier won’t significantly affect their population levels.

Will the UVC clarifier help keep my fish from getting sick?

The UVC clarifier helps to keep aquariums clean and healthy, but it is not a treatment for sick fish. Always consult your local aquatics retailer for assistance in preventing or treating aquarium fish diseases.

My fish have ich, will the UVC clarifier cure them?

In general, parasites are too large to be effectively terminated by UVC light. To treat ich, we recommend consulting your local aquatics retailer for assistance.

I am treating my fish with medication. Should I continue to run the UVC clarifier while doing so?

In order to ensure the most effective treatment, the UVC clarifier should be unplugged while medicating fish.

How do I know the UVC clarifier is working?

The 24-hour timer features an operating status light. If it’s green, the UVC bulb is functioning normally. If it’s red, the bulb has expired and the UVC clarifier must be replaced.

How long should I run the UVC clarifier for?

We recommend first running the UVC clarifier intermittently, for 4 hours a day. If the desired effects are not achieved, gradually increase the amount of time the unit runs each day until they are.

How will the UVC clarifier work following a power interruption?

The UVC clarifier will revert to the same operating time that was initially selected once it is reconnected to a power source. For example, if the timer was set to operate for 4 hours a day, it will continue to operate for 4 hours from the moment power is re-established. As the timer does not keep track of the time of day, if you want the UVC unit to run for 4 hours a day as of 8 am, for example, the unit should be connected to a power source at 8 am.

What size hosing does the UVC clarifier accept?

The UVC clarifier connects in-line to all canister filter hosing with an internal diameter of 5/8″ (or 16 mm), such as the Fluval 07 series.

Does the UVC clarifier need to be mounted with the mounting screws or can it hang in-line with the hosing?

We strongly recommend mounting the UVC clarifier with the two mounting screws provided. The unit should be mounted vertically, with the hose connections at the top and the mounting screws at the bottom.

Is there a particular orientation the UVC clarifier should be mounted?

The UVC clarifier should be mounted vertically, with the hose connections at the top and the mounting screws at the bottom.

My filter stopped operating for a few hours but the UVC clarifier was still plugged in and working. Is it safe to continue using the unit or does it need to be replaced?

The unit is safe to continue using.

I accidentally dropped my UVC clarifier. How do I know if the bulb is broken? Should the unit be replaced as a precaution?

It is not possible to open the UVC clarifier to verify if the bulb is broken. As such, we recommend replacing the unit as a precaution.

What makes a CCFL bulb better than traditional fluorescent bulbs?

A Cold Cathode Fluorescent Light (CCFL) runs cooler than a traditional fluorescent bulb and as such lasts up to 3 times longer.

Packaging sizes: UVC Unit (item no. A203)

Additional information


UVC Unit

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