Tunze Comline® DOC Skimmer 9012

Tunze Comline DOC Skimmer 9012 is an internal protein skimmer designed for efficient organic waste removal in marine and reef aquariums. Its compact construction allows installation directly inside the display aquarium, eliminating the need for a separate sump or external plumbing.

The skimmer removes dissolved organic compounds before they break down into nitrate and phosphate. Air and water are mixed to create fine bubbles that attract dissolved waste. The bubbles transport these compounds through the foam riser and into the collection cup.

Early removal of organic waste supports clear water, more stable nutrient levels, and suitable conditions for marine fish and corals. Intensive mixing also improves gas exchange and helps maintain aquarium oxygen levels.

Comline DOC Skimmer 9012 delivers an air capacity of approximately 400 litres per hour. Depending on biological load and livestock sensitivity, it is recommended for marine aquariums between approximately 300 and 1,000 litres.

The nominal 1,000-litre rating applies to systems containing soft corals, leather corals, long-polyp corals, and anemones. For LPS and mixed reefs, the practical maximum recommendation is approximately 600 litres. SPS-dominated reefs should be limited to approximately 400 litres, while heavily stocked SPS systems should be limited to approximately 300 litres.

Its compact 140 × 110 mm footprint occupies very little aquarium space. The black Comline housing blends discreetly with the aquarium background and keeps visible equipment to a minimum.

The Silence Magnet Holder provides secure installation on aquarium glass up to 15 mm thick. Magnetic attachment also makes height adjustment, removal, and maintenance convenient.

The recommended immersion depth is approximately 255–285 mm. Maintaining the correct and stable water level is important for consistent foam formation. An automatic top-off system can help prevent evaporation from changing the operating depth.

The collection cup has a capacity of 0.7 litres and can be removed for emptying and cleaning. Clean the cup neck and foam riser regularly because organic deposits gradually restrict foam movement and reduce performance.

Power consumption is only 13 W, making the skimmer economical for continuous operation.

A new protein skimmer normally requires an initial running period. Foam production may be inconsistent and a small number of microbubbles may appear during the first days. Performance normally stabilizes after a natural biofilm develops inside the unit.

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 adding new products or performing aquarium maintenance.

Key features

• Compact internal protein skimmer
• Designed for marine and reef aquariums
• Recommended for 300–1,000 litre aquariums
• Air capacity of approximately 400 l/h
• Low power consumption of 13 W
• Collection cup capacity of 0.7 l
• Installs directly inside the aquarium or sump
• No external plumbing required
• Silence Magnet Holder
• Suitable for aquarium glass up to 15 mm thick
• Compact 140 × 110 mm footprint
• Quiet and energy-efficient operation
• Supports the removal of 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 1,000 l
• LPS corals and mixed reefs: up to approximately 600 l
• SPS-dominated reefs: up to approximately 400 l
• Heavily stocked SPS reefs: up to approximately 300 l

Consider the actual system volume, fish population, feeding level, coral sensitivity, and other nutrient-control methods when selecting a skimmer.

Technical information

• Product number: 9012.000
• Recommended aquarium size: 300–1,000 l
• Air capacity: approximately 400 l/h
• Power consumption: 13 W
• Power supply: 230 V / 50 Hz
• Recommended immersion depth: approximately 255–285 mm
• Collection cup volume: 0.7 l
• Dimensions: 140 × 110 × 415 mm
• Magnetic holder: for glass up to 15 mm
• Installation: inside the display aquarium or sump

Installation and setup

1. Select an area with a stable water level.
2. Provide at least 140 × 110 mm of installation space.
3. Leave sufficient clearance above the unit for collection-cup removal.
4. Attach the skimmer with the Silence Magnet Holder.
5. Set the immersion depth to approximately 255–285 mm.
6. Make sure the air intake remains open and free from salt deposits.
7. Keep the plug and electrical connections dry.
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 regularly.
11. Clean the collection cup and foam riser as required.
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.