16" Shadow Overflow - Synergy Reef Systems

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16" Shadow Overflow - Synergy Reef Systems

100% Recommend this to a friend (4 of 4)

SKU: 210377

reg. $199.99

Special Price: $159.99

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Quick Overview

Up to 1500 GPH Flow Rate

Synergy Reef Systems Shadow Overflow is one of the most sought after overflows on the market today. Here at BRS almost any tank we set up will incorporate the Synergy Reef Overflows for their extensive feature list and reliability.

  • Low Profile

  • Injection Molded

  • Removeable weir

  • Failsafe operation

  • Completely silent

  • Years of research & testing

Note: 65mm drill bit required for installation (sold separately)


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Product Questions

The note in the Quick Overview states that a 65mm drill bit is required but the installation guide says that a 63mm or 2.5" bit is required. Will either work??

Question by: Steve on Dec 16, 2016 8:37:00 AM
Hey there,
The difference between a 63mm and 65mm bit would be minimal and either would work. As we don't carry a 63mm bit option, we recommend our 65mm as an alternative to the manufacturer's suggestion, which will also work.
Answer by: Zack (Admin) on Dec 22, 2016 4:18:00 PM
Does this take a 65mm hole saw, as stated on here, or a 63mm, as recommended on the Synergy page?
Question by: BC on Dec 18, 2016 10:45:00 AM
Hey there,
The difference between a 63mm and 65mm bit would be minimal and either would work. As we don't carry a 63mm bit option, we recommend our 65mm as an alternative to the manufacturer's suggestion, which will also work.
Answer by: Randy (Admin) on Dec 22, 2016 6:32:00 PM

Full Details

Install Guide


Drilling Guide


Low Profile

The low profile design of the Shadow Overflow makes it perfect for reef tanks, along with other types since it does not take up that much space inside of the tank. The internal portion of the overflow is only 1.6" thick at its widest point allowing you to fully aquascape your tank without worrying about corals growing into the overflow box.


Injection Molded - Made in the USA

Allowing for tight tolerances and 1-piece construction Synergy Reef removed many points of failure that other overflows have. With no glued seams and strict quality control every overflow is now identical. Synergy Reef is the only company using injection molding techniques for this type of overflow design.



The tapered design of the VTeeth™ keeps the water level in the tank much more steady with flow changes and fluctuations. The increased surface area of the VTeeth™ increases its surface skimming ability directing the dirty water down into your sump to be filtered.


Removable Weir

Keeping your weir clean will lead to much more effective surface skimming and filtration ability. The snap-fit weir will securely mount to the Shadow Overflow and can easily be removed for maintenance and cleaning. Also, the design of the VTeeth™ makes cleaning them much easier than standard overflow teeth.


Failsafe Operation

Having different plumbing methods available with the Shadow Overflow system, the most common and suggested overflow method is the Bean Animal system that uses 3 dedicated drain pipes. The three pipes include; the main drain, secondary drain and an emergency drain making the overflow system completely silent and failsafe.


Years of Research & Testing

With years of real world testing and design, Synergy Reef has designed and tested numerous styles of overflows allowing them to incorporate all of the valuable aspects and designs of different overflow systems into the Shadow Overflow. There are a couple of clones out on the market, but none are built and tested and built like the Shadow Overflow system.



Min tank thickness - 1/4" glass or acrylic

Max tank thickness - 3/4" glass or acrylic

Front Box

  • 16" L x 1.6" W x 5.5" H
  • VTeeth - easy to clean weir design
  • Molded Bulkheads


Rear Box

  • 16" L x 3.75" W x 7" H
  • 3x 1.5" ABS Slip Bulkheads
  • 2x U-flow fittings
  • Removable Rear Cover


What's Included?

1x Front Overflow Box

2x Removable Polycarbonate Front Weirs

2x Polycarbonate Bulkhead Nuts

1x Seamless Rear Box

3x 1.5" ABS Slip Fittings

2x U-Flow 90º fittings

4x Gaskets

1x Drilling Template

1x Installation Manual


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4 Items

  • Best Bang for the Buck By JCA on 1/23/2017

    I think this is the best overflow you can buy right now. Perfect for my 120g.
  • Amazing! By HyphyMike on 12/22/2016

    I purchased this for my 20L and it performs fantastic. I cant hear it at all. Ever.
    Its built amazing!
  • Beautiful! By Jeff on 12/12/2016

    Pre ordered this and just got it the other day for a new 150g build. Craftsmanship and engineering really show with this product. I was nervous as I've always had previously drilled reef ready setups but this thing is so clean!
  • Well designed product By GMB on 12/12/2016

    I bought the 16" model last year when i redid my tank. Low in tank profile is great. Only drawback is that acrylic scratches real easy. A permanent black magic marker takes care of scratches.