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Tunze 9004 Comline DOC DC Protein Skimmer


Starting at $20/mo with . Learn more

Item #: TZ790041

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Tunze Comline DOC DC Protein Skimmer 9004 (9004.001)

The same popular 9004 skimmer is now available with an efficient DC pump!

The new Tunze Comline® filters opens the way for compact aquarium components designed for internal operation, are ultra-functional and are highly-sophisticated. The system creates a natural atmosphere in the aquarium at a minimum size. The goal always remains the same, more performance and less space.

The Comline® DOC Skimmer 9004 is designed for use in seawater mixed aquariums / soft coral aquariums up to 250 litres (66 USgal.) or sensitive reef biotopes with stone corals up to 150 litres (40 USgal.). It works based on the TUNZE® Flash Skimming principle, water supply is provided via an efficient surface intake system with bacteria film removal. Thus, the system can also be used as a “standalone solution” in the aquarium. The featured TUNZE® Foamer generates many fine air bubbles with a diameter between 0.1 and 0.3mm, which ensures particularly silent operation.

The “Flash skimming” principle enables highly efficient foam production.
Principle: Protein-rich surface water is mixed with water thoroughly in the TUNZE® Foamer. On the surface of the air bubbles forming, pollutants such as protein, cellulose, dead cells, etc. are adsorbed immediately, the air bubbles are very fine, with a diameter between 0.1 and 0.3mm. The water/air mixture is expanded and stabilized in the skimmer cup, the water returns to the aquarium, and the protein-loaded air bubbles reach the skimmer cup reactor. The patented anti-overfoaming system intermediate chamber with phase water prevents the skimmer from overfoaming and controls the skimmer performance, depending on the water level and organic load.
The particularly high efficiency of the “flash skimming” principle compared to large skimmers with long contact time is obtained because the substances adsorbed by the air bubbles are not released again, thus they don`t return to the aquarium water again.


  • Surface intake with bacteria film removal.
  • Skimmer cup, 0.2l (.05 USgal.) volume, also accommodates the foam reactor, easy to remove.
  • Attachment with a patented magnet holder for a glass thickness of up to 1/2".
  • Intermediate chamber with patented anti-overfoaming system.
  • TUNZE® Foamer 9004.040, high air output and low energy consumption (4W).
  • Bubble-free outgoing water.
  • New “Comline® Design”: comfortable use, elegant and unobtrusive in the aquarium.
  • Air flow regulation and silencer for an exceptionally quiet operation.
  • Made in Germany, 2-year manufacturer`s warranty


  • Dimensions: 4.3" x 3.5" x 12"
  • Water Lever Required: Approx. 8.86" - 9.65"
  • Air Output: Approx. 150 L/H
  • Energy Consumption: 5W
  • Tank Size: 15-65 gallons
  • Mounts aquariums up to 1/2" thick

Includes magnet mounts

Manufacturer information

For forty-five years the name TUNZE® has been synonymous with aquariums. Many products and components which we have developed in the course of time are now standard features of aquarium technology today. This confidence in TUNZE is no coincidence. The company has remained true to its philosophy right from the beginning, researching water biotopes all over the world to develop components which enable natural water conditions in the closed environment of an aquarium. In the implementation of know-how, effectiveness and efficiency, TUNZE® takes the lead in environmental compatibility. Their motto is: quality and reliability. These values are upheld with well thought-out and precise tool making by highly qualified experts. The brand names of TUNZE® and Turbelle® meet the expectations of the seal of quality; Made in Germany. Many of the products shown in this catalogue are protected by national and international patents.

5 Stars


Reviewed on
March 31, 2020

Yes, I would recommend this.

Great Skimmer

Pros: Very power efficient

Cons: The clips holding the magnet could be beefed up

Using for my 32g biocube and it works great and silent.
Tunze always makes quality products

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Reviewed on
March 23, 2020

Yes, I would recommend this.

Tunze Skummer 9004

Pros: Efficiency, Design

Cons: None

This is an exceptional skimmer for its size. I was a little hesitant at first to purchase due to the size. I have a 20 gal nano reef with no external sump setup so I needed to place the skimmer in the display. The 9004 started skimming waste within 24 hr. Very Impressive! German engineering at its finest. All in all very pleased with this purchase and would recommend it for a nano tank.

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Reviewed on
December 24, 2019

Yes, I would recommend this.

great skimmer

Pros: powerful in a small package. easy to control.

Cons: air intake can become clogged with salt.

i have been running this skimmer for over 2 years on a 50 gallon reef. Great production, very efficient for its size. Excellent fine tune controller. Needs to be disassembled annually for cleaning.

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Reviewed on
September 18, 2019

Yes, I would recommend this.

great skimmer

Pros: Easy setup. Very quiet, DC makes its easy to tweak, just speed up or slow down the pump. Well built.

Cons: Haven't found any yet except for the price, but there ohs nothing cheap about this hobby.

Great skimmer. Had it set up and pulling gunk out of my 40 gal on the first day.

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Reviewed on
September 10, 2019

Yes, I would recommend this.

Great Skimmer

Pros: Very quiet, making skim mate right out of the box, seems to be very well built

Cons: Not really a con but you need to be aware that this skimmer is an in tank skimmer with the working sections being in your tank, unlike a hang on back skimmer where most of the skimmer is outside the tank.

Been in the hobby for 25 years. Had tanks ranging from 10 gal to 210 mixed reef. This is the first skimmer I found that starting skimming right out of the box the first day. This is also the most quiet skimmer I have ever had. Wouldn't even know it was running.
Controlable pump/bubble maker is a fantastic idea. Will be fine tuning it over the next few days but so far I am really happy with this purchase.

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Reviewed on
October 22, 2018

Yes, I would recommend this.

Awesome AIO Skimmer

I have mine set up and running on a IM Fusion 40 tank and it's working great. Like others note, it does skim a little wet but awesome overall.

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Reviewed on
October 06, 2018

Yes, I would recommend this.

Great product, annoying assembly

Pros: Quiet, efficient.

Cons: Difficult to assemble/disassemble for cleaning and maintenance.

This skimmer works great amd very quiet. The external control to allow temporary shut off is also a thoughtful design to allow easy collection cup cleaning. The only reason I am not rating this at five star is that when I first received the unit all of the unit’s internals got messed up from the shipping process and I had to disassemble to organize all parts then reassemble for the unit to function. That’s not the bad part. The bad part is that while disassembling and reassembling I realize how much of a pain in the ass the unit assembly is for future seasonal maintenance (cleaning the propeller and scrub off sponge growth, etc.). The unit would be a five star if the product designer can consider a way to allow average aquarist a mess free, easier time to disassemble the unit for thorough maintenance. But overall this is a product I would recommend.

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Reviewed on
May 29, 2018

Yes, I would recommend this.

Great Skimmer

my only comparison point is the IM ghost skimmer which i had in my IM30L tank. night and day comparison, the tunze day 1 start pulling nasty out of the tank and was super easy to dial in. the only drawback compared to the ghost skimmer in my case is i lost one of the compartments of my AIO to the skimmer which was mechanical filtration before due to size. still worth it, the ghost after a month barely pulled anything and was super loud.

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Reviewed on
December 19, 2017

Yes, I would recommend this.


Great little skimmer. Took a bit to get dialed-in but it's been running perfectly for a couple of weeks now. Side note, I have mine installed in-tank... it fits snuggly between the two outputs of the JBJ Rimless 45. That freed up the back chambers for significantly upgraded mechanical, biological, and chemical filtration.

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Reviewed on
January 06, 2017

Yes, I would recommend this.

Very Good Skimmer

Pros: Effective

Cons: Be careful and watch your water level to maintain a good skim

Not too bad to adjust. Skims a little wet but does a great job. Very Happy with this one.

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