SUNSUN HW-303B External Canister Filter

SunSun HW 303B External Filter with UV for Clear Water and Powerful Aquarium Filtration

The SunSun HW 303B External Filter with UV is a high-performance external canister filter made for aquariums that require strong circulation, reliable water polishing, and extra UV clarity support. With a 1400 litres per hour flow rate and 35W pump power, it is suitable for aquariums up to around 100 gallons, depending on stocking level, feeding routine, aquascape layout, and maintenance frequency. It is a practical option for freshwater aquariums, planted tanks, cichlid tanks, goldfish tanks, community fish tanks, and marine aquarium systems.

This aquarium canister filter is designed to support mechanical, biological, and chemical filtration. Mechanical filtration helps trap fish waste, plant particles, uneaten food, and suspended debris. Biological filtration supports beneficial bacteria that help maintain a stable nitrogen cycle, while chemical filtration can be added when needed for water polishing, odour reduction, or specific water treatment goals. The spacious media tray design allows aquarists to arrange filter pads, ceramic rings, bio media, activated carbon, fine floss, or other compatible media based on aquarium requirements.

The built-in 9W UV sterilizer gives the SunSun HW 303B an added advantage for tanks where water clarity is important. When used correctly, the UV function helps control free-floating algae spores and bacteria, supporting clearer water and reducing the chance of green water issues. The external design keeps the main display area clean and uncluttered, while the included hoses and setup parts make it easier to connect the filter to the aquarium.

Specifications of SunSun HW 303B External Filter with UV

• Product Type: External canister aquarium filter with UV sterilizer
• Model: HW 303B
• Brand: SunSun
• Flow Rate: 1400 litres per hour
• Approximate Flow Rating: 370 GPH
• Pump Power: 35W
• UV Sterilizer: Built-in 9W UV
• Recommended Aquarium Size: Up to around 100 gallons
• Maximum Head Height: Approximately 2.0m
• Voltage: 220–240V
• Frequency: 50Hz / 60Hz depending on variant
• Approximate Dimensions: 10.5 inch L × 10.5 inch W × 16 inch H
• Metric Dimension Reference: Approximately 258mm × 258mm × 430mm
• Approximate Weight: Around 5kg
• Cable Length: Approximately 1.8m
• Filtration Type: Mechanical, biological, and chemical filtration
• Suitable Water Type: Freshwater and marine aquariums
• UV Function: Helps control algae spores, free-floating bacteria, and green water problems
• Included Accessories: Filter pads, hoses, inlet and outlet parts, and basic setup accessories
• Filter Media Note: Filter media may not be included as part of the standard package except supplied pads; additional biological or chemical media may need to be purchased separately

How to Use This External Canister Filter

1. Place the SunSun HW 303B below or beside the aquarium on a flat, stable surface with enough space for hose routing and routine maintenance.
2. Open the canister and arrange the supplied filter pads along with your chosen media such as ceramic rings, bio balls, activated carbon, fine filter floss, or porous biological media.
3. Set mechanical media in the first filtration path to trap visible debris, biological media in the main trays to support beneficial bacteria, and chemical media only when needed for water polishing or targeted filtration.
4. Connect the inlet and outlet hoses securely, making sure all fittings are tight to prevent leaks, air intake, or reduced flow.
5. Position the inlet pipe inside the aquarium where it can pull water effectively without being blocked by plants, rocks, substrate, or decorations.
6. Install the outlet pipe or spray bar so filtered water returns evenly to the tank and creates suitable water movement and surface agitation.
7. Fill the canister with aquarium water if required, close the filter head correctly, and begin the siphon or priming process before powering the unit.
8. Switch on the filter only after water is moving through the canister and check carefully for leaks, trapped air, vibration, or unusual noise.
9. Use the UV sterilizer when extra clarity support is required, especially for green water, algae spores, or free-floating bacterial issues.

Care & Maintenance Tips

• Clean filter pads and sponge media in removed aquarium water to protect beneficial bacteria from chlorine damage.
• Do not replace all filter media at the same time, as this can disturb the aquarium’s biological balance.
• Rinse mechanical media whenever water flow reduces or visible debris accumulates inside the filter.
• Use good-quality ceramic rings or porous bio media to strengthen long-term biological filtration.
• Replace chemical media such as activated carbon according to its usable life and only when required.
• Clean inlet and outlet pipes regularly to prevent algae, biofilm, and sludge from reducing flow.
• Inspect the impeller chamber during maintenance and remove trapped dirt, plant fragments, or sand.
• Check that the canister lid, sealing ring, and locking clips are properly seated after every cleaning session.
• Handle the UV section carefully and never look directly at an active UV lamp.
• Keep the filter running continuously to maintain stable water movement, oxygen exchange, and beneficial bacteria activity.