Fiji Cube

LoPro External Overflow Box (400 GPH)

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Fiji Cube's unique design takes low-profile overflows to the next level!


We were immediately impressed by the thoughtful design and unique features of Fiji Cube's overflow boxes. The wet side overflow box is among the slimmest on the market, but what really sets it apart is the ease of servicing and maintenance that they built into their surface-skimming weirs with a removable, o-ring sealed interface that slides into the bulkhead. The wet side can be easily removed for cleaning or other servicing needs, and slides back in just as easily. There are no annoying bulkhead nuts to remove in tight spaces, so you don't have to worry about completely undoing your dry-side plumbing if you need to remove the weir. This also provides easy access to the tank bulkhead and just makes overall maintenance easier.


4 Sizes to Choose From:

  • 400 GPH (Dual Drain)
  • 800 GPH (Dual Drain)
  • 1,600 GPH (3 Drains)
  • 2,400 GPH (3 Drains)


Fiji Cube also includes a guide template for drilling so that you can get the bulkhead hole positions and water level just the way you want it without any worry. Build quality is top-notch with solid construction and a nice tight fit on all components, and each overflow is designed with multiple drains for redundancy and safety. The smaller 400 GPH and 800 GPH dual-drain systems are perfect for a Herbie style overflow. 



  • Slim and compact design to suit any aquarium set-up
  • Works with rimless, eurobrace, and standard trim aquariums
  • Entire skimmer box pulls off for routine maintenance
  • 3/8” thick acrylic mounting wall and base on exterior box
  • Front and back lid cover included to quiet noise
  • Template & diamond hole saw included
  • PVC pipe included for emergency drain
  • Primary & emergency drain bulkheads; perfect for Herbie style drains



  • Skimmer Box Dimensions: 4"L x 1.25"W x 3.5"H
  • Exterior Box Dimensions: 5"L x 3.5"W x 5.25"H
  • Max Flow Rate: 400 GPH
  • Drain Bulkead Size: 3/4" x 2
  • Max. Tank Thickness for Mounting: 14mm


What's Included?

  • Fiji Cube 400 GPH LoPro Overflow assembly
  • Glass Drill Bit & Hole Guide


pdf Fiji Cube Low Profile Overflow Instruction Manual


More Information
UPC 761856629790
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Product Questions

What is the size the of main bulkhead that attaches to the aquarium?
Question by: Anderson Obregon on Dec 18, 2023, 8:12 PM
Hey there,
Thank you for reaching out to us. It is 1.5".

Please let me know if you need anything further and take care!
Answer by: Matt Lucero (BRS Staff) on Feb 15, 2024, 10:01 AM
I just ordered the Fiji Cube 400 overflow... What size drill bit does it come with?

Thank you!
Question by: Robert E Dean Jr on Nov 20, 2021, 6:31 PM
Hello, the Drill Bit is a 60mm hole size. Thanks.
Answer by: Christian (BRS Staff) on Nov 24, 2021, 11:17 AM
What size are the bulkheads for the 400GPH version?
Question by: David N on Mar 30, 2020, 9:20 PM
Hi there,

They will be 3/4" drain bulkheads.

Take care
Answer by: Thomas Billington on Apr 2, 2020, 1:33 PM
How would I attach schedule 40 to the drains? I see they are threaded. Should i need a bulkhead? If so, what size?
Question by: Garrett Bates on Mar 27, 2020, 3:21 PM
Hey there-

Great question! The outside of all bulkheads will be threaded as this is how you screw on the retaining nut to hold it tight against glass/acrylic. The inside of those bulkheads will actually be slip, in which case any standard 3/4" PVC should inside paired with PVC cement.

Happy reefing! c:
Answer by: Brad Ohmann on Mar 27, 2020, 3:42 PM