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Internal Overflow Box 1,800GPH, 12.25"W x 3.75"D x 5"

Product code: 2746

Availability: In stock

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Overflow Box 1,800GPH, 12.25"W x 3.75"D x 5"AO Overflows can help turn your reef aquarium into a high performance aquatic environment that will make your coral (particularly your SPS) thrive. Highly effective, the overflow box increases the rate at which surface water is pulled into the filter, reduces surface film and dust by removing water from the area of the aquarium where most organic waste is found.Whether you need to skim water for your sump, your closed head circulation, or external fed powerheads, you should use an overflow box to help protect your inhabitants and provide control over the amount of water leaving your tank.

Overflow Box 1,800GPH, 12.25"W x 3.75"D x 5".

12 ¼”W x 4”D x 5”T

Works great with 120-210 gallon aquariums

Made from ¼” Black Cast Acrylic

4-Sided (Front, 2 Sides, and Bottom)

All joints are water tight.

Recommended Return Pump of 1800 gph or less.

Easy Installation Using Our 100% Silicone Adhesive.

* Aquarium needs to be drilled with proper size hole/bulkhead to utilize this overflow box.

Questions on Internal Overflow Box 1,800GPH, 12.25"W x 3.75"D x 5"

  • From James at 2/2/2015 12:40 PM
    • Hi. I purchased an used tank with existing pre-drilled holes. I want to purchase and install this overflow box. I'd like to know how far down should the outlet hole be from the top of the tank. As it stands right now, the hole sits at a little more that 1" from the top of the tank. If this overflow box is 5" tall, I'm assuming the teeth are around 1" tall, which would put it close to level of the outlet hole. Do I need to drill a new hold or can I use the existing one? Please advise and thanks in advance.
    • You should be able to use the existing hole. You may need to create an air vent on the outside of the tank by using PVC Tee just behind the bulkhead to prevent excess noise.
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  1. Simple Solution Review by Lisa

    This Overflow has made my DIY plumbing super simple. Pretty much silicone n play. It's really that easy! (Posted on 7/8/2013)


    I purchased this overflow for my 110 gallon reef aquarium to replace my CPR overflow. It was easy to install and so far has been working great. Plan to buy the lid and a smaller overflow for my frag tank. (Posted on 1/29/2013)


    Only overflow box I've used but the craftsmenship is great and water tight. Measurements of the box are outside dimensions(not inside). (Posted on 1/29/2013)

  4. PERFECT FOR 110G Review by ROBBY

    This overflow fits my 110 gallon aquarium perfect. Allows for tons of flow. My tank has a tempered bottom. This overflow allowed me to drill the back wall of my tank. I will most likely go with this style of overflow for all future setups. (Posted on 1/29/2013)

  5. TWO THUMBS UP! Review by DJ

    I give this weir two thumbs up for easy of installation and durability. Made from thick strong acrylic. (Posted on 1/28/2013)

  6. Finally! Review by Danny

    Finally there's an affordable option for internal overflows! As others already mentioned this overflow installs in minutes. Easy as 1-2-3... Great quality, made from sturdy acrylic. I have no doubt this overflow box will outlast my tank. Also keep in mind that if you ever had to adjust or make any repairs, you only have to drain off the first 5" of water in your tank vs. completely emptying your tank. This is a HUGE plus in my eyes! (Posted on 1/1/2013)

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69.99 In stock