Tunze Comline® DOC Skimmer 9004

Tunze Comline DOC Skimmer 9004 is a compact internal protein skimmer for marine and reef aquariums. It removes dissolved organic compounds before they break down into nitrate and phosphate. Its compact construction allows direct installation inside the display aquarium without a separate sump or external plumbing.

The skimmer mixes air and water to produce fine bubbles. Dissolved organic compounds attach to the bubble surfaces and are transported with the foam into the collection cup. Removing organic waste supports clear water, more stable nutrient levels, and good oxygenation.

Tunze Comline DOC Skimmer 9004 is suitable for marine systems between approximately 60 and 250 litres, depending on their biological load. The practical maximum capacity depends on fish population, feeding, coral sensitivity, and additional nutrient-export methods.

In aquariums containing soft corals, leather corals, long-polyp corals, or anemones, the skimmer can be used in systems up to approximately 250 litres. For LPS and mixed reefs, the recommended maximum is approximately 150 litres. SPS-dominated reefs should be limited to approximately 100 litres, while heavily stocked SPS systems should be limited to approximately 75 litres.

The skimmer produces approximately 150 litres of air per hour. Power consumption is only 4 W, making it economical for continuous operation. Quiet performance makes it suitable for aquariums installed in living rooms, offices, and other noise-sensitive locations.

Its compact 110 × 90 mm footprint occupies very little aquarium space. The black Comline housing blends discreetly with a dark aquarium background and minimizes the amount of visible equipment.

The included Magnet Holder provides secure attachment to aquarium glass up to 12 mm thick. Magnetic mounting also makes height adjustment, removal, and maintenance convenient.

The recommended immersion depth is approximately 225–245 mm. A correct and stable water level is important for consistent foam production. An automatic top-off system can prevent evaporation from changing the operating depth.

The collection cup holds 0.2 litres and can be removed for emptying and cleaning. Clean the cup neck and foam riser regularly because accumulated organic deposits gradually restrict foam movement.

A new protein skimmer normally requires a short running-in period. Foam production may be inconsistent and a small quantity of microbubbles may appear during the first days. Performance normally stabilizes after a natural biofilm develops inside the skimmer.

Water conditioners, coral adhesives, aquarium additives, oily foods, and other substances that affect surface tension may temporarily change foam production. Monitor the collection cup carefully after aquarium maintenance or the addition of new products.

Key features

• Compact internal protein skimmer
• Designed for marine and reef aquariums
• Recommended aquarium size of 60–250 litres
• Air capacity of approximately 150 l/h
• Low power consumption of 4 W
• Collection cup capacity of 0.2 l
• Installs inside the display aquarium or sump
• No external plumbing required
• Includes Magnet Holder
• Suitable for glass up to 12 mm thick
• Compact 110 × 90 mm footprint
• Quiet and energy-efficient operation
• Removes dissolved organic compounds
• Helps limit nitrate and phosphate formation
• Supports gas exchange and oxygenation
• Removable collection cup
• Suitable for continuous operation

Aquarium sizing

• Soft corals, leather corals, and anemones: up to approximately 250 l
• LPS corals and mixed reefs: up to approximately 150 l
• SPS-dominated reefs: up to approximately 100 l
• Heavily stocked SPS reefs: up to approximately 75 l

Consider the actual system volume, fish population, feeding level, coral sensitivity, and additional nutrient-export methods. Select the skimmer conservatively for heavily stocked or intensively fed aquariums.

Technical information

• Product number: 9004.000
• Recommended aquarium size: 60–250 l
• Air capacity: approximately 150 l/h
• Power consumption: 4 W
• Power supply: 230 V / 50 Hz
• Recommended immersion depth: approximately 225–245 mm
• Collection cup volume: 0.2 l
• Dimensions: 110 × 90 × 305 mm
• Magnetic holder: for glass up to 12 mm
• Installation: inside the display aquarium or sump

Installation and setup

1. Select an area with a stable water level.
2. Provide at least 110 × 90 mm of installation space.
3. Leave sufficient clearance above the unit for removing the collection cup.
4. Attach the skimmer with the included Magnet Holder.
5. Set the immersion depth to approximately 225–245 mm.
6. Make sure the air intake remains open and free from salt deposits.
7. Keep the plug and electrical connections dry and protected.
8. Create a drip loop in the power cable.
9. Start the skimmer and monitor operation during the first days.
10. Check collection-cup filling frequently during the running-in period.
11. Clean the collection cup and foam riser regularly.
12. Maintain the pump, air intake, and impeller chamber according to the instructions.
13. Disconnect the equipment before maintenance or placing hands in the aquarium.