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Marine Depot Overflow Box OF-1200

Item #: MD8135

We no longer carry this item

High quality and economical hang-on overflow box allows you to easily add a sump, refugium or wet/dry filter to your system. U-tube design allows for easy and convenient installation. Adjustable pre-filter height allows you to adjust the water level inside your aquarium.

  • 2 x 1" Bulkhead
  • U-tube
  • Noise-Reducing Cylinder Foam Sleeves
  • Nylon screw and wing nut
  • Surface Skimmer Box
Model Tank SizeMax. Rim Size Overflow Body
Surface Skimmer
Max. Flow Rate Drain Size
Nano up to 30 Gal1.5" 4"x2.5"x8" 4"x1.5"x6" 200GPH 3/4"
OF-300 up to 60 Gal1.5" 6"x3"x10" 6"x2.5"x6" 300GPH 1"
OF-800 up to 120 Gal1.5" 8"x3"x10" 8"x2.5"x6" 800GPH 1"
OF-1000 up to 150 Gal1.5" 9"x3"x10" 9"x2.5"x6" 900GPH 2 x 1"
OF-1200 up to 200 Gal1.5" 10"x3"x10" 10"x2.5"x6" 1000GPH 2 x 1"
OF-1800 up to 320 Gal1.5" 12"x4"x10" 12"x2.5"x6" 1600GPH 1-1/2"

Manufacturer information

Marine Depot was started in 1998 by a self-professed reef geek and pre-med student Ken Wong. Ken envisioned a one-stop shop where customers could find everything they needed, from technical product specifications, reef aquarium information, expert advice on the hobby and friendly one-on-one customer support. Having grown from a one-man crew to being one of the world’s largest suppliers of reef and marine aquarium products, this very core philosophy still lives strong in the Marine Depot culture 20 years later.


Reviewed on
July 08, 2020

No, I would not recommend this.

I dont know how this has such good reviews.

Pros: Havent found any yet. Too many cons out of the box.

Cons: Bulkheads leak like crazy and require a lot of extra work to get them leak free.

I am disappointed to say the least. I am a very experienced fish tank keeper and this is one of the worst purchases I've made. The boxes are well constructed but the bulkheads and fitting of them are terrible. They leak like CRAZY as is. Add an extra oring and plumbers tape, STILL leaks. I had to silicone the inside and outside, along with plumber's tape and an extra o ring to get ONE to stope leaking and the other I'm still working on. I cant believe they sell these like this. This is not worth the time and outright hassle to get this thing to the point of being able to see if it works (still not there). Dont waste your money. I'll be replacing it.

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Reviewed on
May 07, 2020

Yes, I would recommend this.

Great overflow

Pros: Starts back up when power fails

Cons: None

So I did some research for a hob overflow and was gonna get another brand (sold here) well after reading stories about the pumps failing and the box losing siphon noooopppeee. So I went with this it's cheaper than any others on the market and when you lose power and power comes back IT STARTS BACK UP no wet floors awsome. I highly recommend it

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Reviewed on
February 07, 2020

Yes, I would recommend this.

Great for the money

Pros: Great for the money

Cons: No stickers

Originally I was gonna get the cpr overflow as my tank is not drilled but after reading horror stories I went with this style. I've had it running for a few months with no issues, it also will auto stop and start if there is a power outage.

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Reviewed on
November 16, 2019

Yes, I would recommend this.

Works like a charm

Pros: Very quiet with minor modification, handles a *lot* of water, practically invisible at the back of your tank with the right background and lighting.

Cons: Without modification its extremely noisy

Bought this overflow for my 75g African cichlid tank. I know technically its overkill for that sized tank but theres a reason why. HOB overflows are notorious for being super noisy. This can be fixed by getting one that has two drains, cutting two pieces of PVC (one that sits just below the waterline in the overflow box, and one about 1.5-2" higher) to replace the stock ones with the sponges. Have a gate valve on the drain with the shorter pipe, and tune it so that the water level in the overflow box sits half way between the two pipes. No more air will get sucked but if the primary drain gets clogged the water will only rise till it hits the secondary "emergency" drain. With this modification this overflow box is whisper silent and works great!
I'd like to give a shoutout to the marine depot customer service team as well. When I purchased one of the bulkheads was faulty, it had some deformities from casting that caused a slow leak. I emailed them on a Sunday night not expecting a reply till later Monday. I received an email back on the same Sunday night and they had a replacement in the mail the next morning. Outstanding customer service.

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Reviewed on
September 17, 2019

Yes, I would recommend this.


Easy to install. Very efficient.

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Reviewed on
February 14, 2019

No, I would not recommend this.


Pros: N/A

Cons: N/A

Came broken! i am trying to conact customer aupport impossible no one answer the phone!!

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Reviewed on
February 14, 2019

No, I would not recommend this.


Fist time ordering from maninedepot and came broken, I immediately called the number on the receipt that came in the box and no one! answer more than 25 min waiting! is frustrating

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Reviewed on
September 17, 2018

Yes, I would recommend this.

Marine Depot Overflow Box

Pros: Good water flow And well built

Cons: Can generate some noise

I purchased the OF-1200 and am very happy with it. I have had no issues and it does what it’s supposed to do. I have it 4 stars because it’s a little loud and an air bubble keeps popping up in the tube, however I’m sure it’s just operator error. Overall I’m very happy with the product and would recommend this to a friend.

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