Target dinoflagellates where they grow

Sand-dwelling dinoflagellates can be difficult to reach with a conventional in-line UV sterilizer. The ReefSweep Medium brings a 7W UV-C module close to visibly affected areas of the sand bed in a marine aquarium. It is designed for use in small to medium reef tanks.

Place the treatment head on or just above the affected area, with its opening facing the sand. The enclosed head helps direct the UV-C light towards the selected spot.

Use the ReefSweep Medium as part of a broader approach to identifying dinoflagellates and addressing the conditions behind an outbreak. Results can differ between species and aquariums.

Why choose the ReefSweep Medium?

• Targeted sand-bed treatment: positions UV-C close to visibly affected areas.
• 7W UV-C module: supplied with an inline on/off switch.
• Modular handle: two extension tubes, one connector and a separate handle.
• Designed for small to medium tanks: approximately 60 cm tall when fully assembled.

The 60 cm measurement is the total assembled height, including the treatment head and handle. It is not a maximum water-depth rating: leave enough room to grip and move the handle above the aquarium rim. The switch must remain outside the aquarium.

How to use

1. Assemble the treatment head, extension tubes, connector and handle.
2. Position the head on or just above a visibly affected area, with the opening facing the sand.
3. Ensure that the entire treatment head is submerged before switching on the UV-C module. Keep the switch and electrical connections dry and outside the aquarium.
4. Treat the selected area in accordance with the instructions supplied with the UV-C module.
5. Switch off and unplug the module before lifting the treatment head out of the water.

Reducing the flow from your circulation pumps temporarily may make it easier to hold the head over one spot.

Why can dinoflagellates take over?

Dinoflagellates can gain ground when aquarium conditions favour them and other micro-organisms lose their foothold. Prolonged very low or undetectable nitrate and phosphate, a loss of biodiversity or sudden changes in maintenance may play a part. An outbreak is also possible when nitrate and phosphate are measurable; test values alone do not reveal the cause.

Supporting the aquarium after treatment

UV-C treats a selected area, but long-term management also means looking after the rest of the aquarium. Some reef keepers add a suitable bacterial culture after treatment and introduce copepods to support microfauna. Both are optional additions, not a guaranteed cure or a required dose after every session. Follow the bacterial product's directions, including any instructions about switching off UV equipment, and monitor nitrate and phosphate. Copepods need suitable habitat and food to establish.

What's included?

• 1 × ReefSweep Medium treatment head
• 1 × 7W UV-C module with inline on/off switch
• 2 × extension tubes
• 1 × connector
• 1 × handle

Important safety information

Do not use in acrylic aquariums (Plexiglas).

UV-C light can damage eyes and skin. Only switch on the module when correctly installed, with the treatment head fully submerged and facing the sand. Never look directly at the light or its reflection. Do not expose fish, corals, invertebrates or other aquarium surfaces directly to UV-C.

Keep the switch, plug and electrical connections dry, use a drip loop and stop using the module if the cable or housing is damaged.

The ReefSweep Medium is a targeted treatment tool, not a guaranteed standalone cure for every dinoflagellate outbreak. Correct identification and addressing underlying aquarium conditions remain important.