Reef Octopus

Classic 2000 Hang-on-Back Protein Skimmer

In stock

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HOB skimmer with pump mounted externally under the skimmer body. Unique external pump design reduces heat exchanged to the water. Easy removal of the pump for cleaning and maintenance. Powered by Aquatrance 2000s skimmer pumps with improved venturi design and pinwheel impeller. Built with high-quality acrylic.



  • Low Profile body
  • Powered by Aquatrance 2000s Skimmer Pump
  • High performance venturi air injection system
  • Low Heat and Energy Efficient Performance
  • Pump Mounted Externally
  • Surface Skimmer
  • Air Silencer
  • Solid Acrylic Construction



Recommended Sizing

  • Heavy Bioload - 75 gallons
  • Medium Bioload - 100 gallons
  • Light Bioload - 175 gallons



  • Manufacturer rates skimmer for tanks up to 200 gallons
  • BRS Recommends this skimmer for tanks up to 100 gallons
  • Dimensions: 10" x 4" x 21"
  • Max Tank Thickness: 1.75"
  • Uses metric plumbing parts
  • Skimmer Pump: Aquatrace 2000s
  • Max Flow: 198 GPH
  • Power Consumption: 18 watts
  • 1 year warranty on skimmer and pump




pdf Owners Manual

More Information
SKU 204059
UPC 6950291203113
Skimmer Type Hang On Back
Capacity Light Bioload - Up to 175 gallons
Medium Bioload - Up to 100 gallons
Heavy Bioload - Up to 75 gallons
Dimensions 10"L x 4"W x 21"H
Max Tank Thickness 1-3/4 in.
Flow Rate 198 GPH
Pump Model Aquatrace 2000s
Pump Rotor Type Pinwheel
Variable Speed No
Power Type AC
Power Consumption 18 watts
Warranty 1 Year
Additional Notes The manufacturer rates skimmer for tanks up to 200 gallons, but BRS recommends this skimmer for tanks up to 100 gallons
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Product Questions

would this be a good skimmer for a 40 gallon set up for a reef tank ? medium bio load.
Question by: Ronald Pinckard on Nov 3, 2022, 11:04 AM
The Reef Octopus Classic 2000 Hang On Back Skimmer, may be a bit too strong for a 40 gallon system. It is rated for 75-175 gallons total volume based upon bioload. The Aquamaxx HOB 1.5 would probably be a better fit for your setup.
Answer by: Scott F. (BRS Staff) on Nov 9, 2022, 10:33 AM
I have read most of the reviews and I can to the conclusion overall a good skimmer.
Im new to the hobby and I need a skimmer but I’m worried that I will have issues with dialing it in or tune it correctly. Is this skimmer fairly easy to handle for beginners?
Question by: Julia Rumpler on Dec 17, 2021, 2:16 PM
Hey there,

Yes that skimmer is fairly easy to dial in as the way to adjust it is going to be moving the cup and sliding the o-ring on the collection cup down or up depending on the foam height you are trying to achieve.
Answer by: Codey on Dec 21, 2021, 1:59 PM
hi I'm looking at hanging this off my sump how many inches is needed from top of tank to bottom of skimmer?
Question by: Nick miller on May 27, 2017, 4:31 PM
Due to the added head height that the pump would have to draw the water up from the sump, I'm afraid this skimmer is not meant to operate on the back of a sump and would only be designed to work on a display tank. Beyond that, you will need a little over a foot of clearance below the rim for the body and pump.

Answer by: Zack on Jun 5, 2017, 3:05 PM