SUNSUN CUV-218 UV Sterilizer

The SUNSUN CUV-218 UV Sterilizer is a powerful UV-C water clarifier designed to improve water clarity and help control suspended algae, bacteria, and other microorganisms in aquarium and pond filtration systems. It uses an 18W UV-C lamp to treat water as it passes through the sterilizer. The internal spiral/helix water-flow design increases the water’s exposure to UV-C light, helping improve treatment efficiency.

The CUV-218 is rated for a maximum water capacity of up to 20,000 litres and a recommended/maximum through-flow of around 2,500 L/h, depending on the application and installation. It is suitable for freshwater and marine systems and can be integrated into an existing pump-and-filter setup.

Powerful 18W UV-C Sterilization

The CUV-218 uses an 18W UV-C lamp. UV-C radiation helps control suspended algae and microorganisms as water passes through the enclosed UV chamber. This makes it particularly useful for reducing green water and maintaining clearer-looking water.

Internal Helix Water-Flow Design

An internal helix guides the water through the UV chamber in a controlled spiral flow. This increases the contact time between the circulating water and UV-C radiation compared with a simple straight-through design, supporting more effective water clarification.

Helps Control Green Water

The SUNSUN CUV-218 is especially useful when suspended algae cause green or cloudy-looking water. UV treatment helps control these free-floating algae so they can subsequently be captured by the mechanical filtration system.

Suitable for Large Aquariums & Ponds

According to SUNSUN's specifications, the CUV-218 has a rated capacity of up to 20,000 litres. It is therefore well suited to larger aquarium systems, koi ponds, garden ponds, and other water features when correctly sized and installed.

2,500 L/H Water Flow

The unit has a listed through-flow of 2,500 L/h. Proper flow control is important because UV effectiveness depends on how long the water remains exposed to the UV-C radiation.

Multiple Hose Connection Sizes

The CUV-218 supports multiple hose sizes using its supplied adapters. Specifications list connections around 20/25/32/38 mm, making it easier to integrate the sterilizer into different filtration and pond plumbing setups.

Easy Operation & Monitoring

The unit features an indicator/viewing section that allows the user to check whether the UV lamp is operating. This makes routine monitoring easier without having to open the UV housing.

Built-In Protection

The CUV-218 incorporates protective features designed for reliable operation, while its enclosed UV chamber keeps the UV-C lamp contained during normal use. UV-C lamps should never be operated exposed because direct UV-C exposure can cause injury.

Long Cable for Flexible Installation

The CUV-218 is supplied with a 5-metre power cable, providing flexibility when positioning the unit around a pond, sump, filtration cabinet, or external filtration system.

Chemical-Free Water Clarification

UV clarification works without adding water-clarifying chemicals. It can therefore be incorporated into a normal mechanical and biological filtration system as an additional water-treatment stage.

Quick Facts

• Brand: SUNSUN
• Model: CUV-218
• Type: UV-C Water Sterilizer / Clarifier
• UV-C Lamp: 18W
• Total Power: 22W
• Maximum Capacity: Up to 20,000 Litres
• Recommended Flow: Up to 2,500 L/H
• Voltage: 220–240V, 50Hz
• Cable Length: 5 Metres
• Hose Connections: 20 / 25 / 32 / 38 mm
• Maximum Pressure: 0.3 Bar
• Suitable For: Aquariums, Koi Ponds, Garden Ponds & Marine Systems
• Main Benefit: Helps control green water, suspended algae and microorganisms
• Water Flow Design: Internal helix/spiral flow for improved UV exposure
• Installation: Can be connected inline with an external pump and filtration system
• Maintenance: Periodic UV lamp and quartz sleeve cleaning/replacement is recommended
• Important: UV-C light should never be viewed directly or operated with the housing open.