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CPR CS90 Overflow Box


Item #: CR1513

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  • For glass or acrylic aquariums up to 125 gal.
  • Flow rate 600 GPH.
  • 7 1/4" wide
  • 1" bulkhead outflow
A built in overflow is the most efficient method of draining aquarium water to a filter. If your aquarium does not have built-in overflow, CPR Continuous Siphon Overflows/Prefilters are the best means for getting water from an aquarium to a filter system without expensive modifications to the tank. They quietly skim up to six times more water than units with tubes.

The advantages of CPR Continuous Siphon Overflows/Prefilters include:
  • Adjustable water level allows you to easily change the level in your tank.
  • Black top reduces algae growth.
  • Quiet operation.
Tip: We recomond the use of an Aqua Lifter pump with the CPR overflows for trouble free operation. Another alternative is to hook the bleed hose from the overflow to the air intake of a power head. This way the overflow will continue to wok if it drawes some air into it or in the event of a power failure it will restart.

CPR Diagram

Model Width A B C D E F G H I J K L
CS50 6" 6 7/8" 8" 1 1/2" 1 7/16" 3 15/16" 4 3/4" 7 1/4" 5 9/16" 4" 3 3/16" 3 1/8" 2 7/8"
CS90 7 1/4" 7 5/8" 9 1/2" 1 5/8" 1 1/2" 4 1/2" 5 1/16" 8 5/8" 5 7/8" 3 7/8" 2 1/8" 3 5/8" 3 3/4"
CS100 9 3/8" 8" 10 1/4" 1 11/16" 1 1/2" 4 11/16" 5 1/16" 9 1/4" 6" 3 7/8" 3 1/4" 3 3/4" 2 3/4"
CS102 9 3/8" 7 7/8" 10 1/4" 1 11/16" 1 1/2" 4 5/8" 5" 9 1/4" 6" 3 7/8" 3 3/8" 3 3/4" 2 3/4"
CS150 9 3/8" 9 7/8" 10" 1 15/16" 1 1/2" 5 3/4" 5 3/4" 9" 6 7/8" 4 1/2" 3 11/16"" 5 1/4" 3 3/8"
CS202 9 3/8" 9 3/4" 10" 1 15/16" 1 1/2" 6 3/8" 5 3/4" 9" 6 3/4" 4 1/2" 3 5/8" 5 1/4" 3 3/8"

Manufacturer information

CPR Aquatic Aquarium Supplies
In Arcata, located in Northern California, the sea is a way of life. From the advanced Marine Biology department at Humboldt State University, just up the hill from CPR’s headquarters, to Humboldt Bay, about a mile west, CPR is nestled in a perfect environment to develop equipment for marine aquariums. CPR was started in a small garage in 1987 to produce biological filters for local aquarists. People who used CPR filters were impressed by the high quality and affordable prices. Word spread and the company grew. Since then, CPR has expanded to a 10,000 sq. ft. production facility and has developed many innovative products over the years. CPR is incorporating new ideas and technologies all the time. Their goal is to allow aquarists to place the highest performing products in their tanks at reasonable prices.

5 Stars


Reviewed on
February 13, 2020

Yes, I would recommend this.

Beautiful overflow

Pros: It is really nicely built and a great look on any tank. It takes up alot of water.

Cons: Doesnt come with screen mesh on the input of t overflow.

It could have a better silencer.

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Reviewed on
March 30, 2018

Yes, I would recommend this.

Build Really Well

Pros: Built really Well

Cons: None As Of Yet

I have yet to put into my system. But its built really well and will serve its purpose in my system...

Was this review helpful? 0 1


Reviewed on
October 29, 2017

Yes, I would recommend this.

CPR CS90 Overflow

Pros: Quality product and function.

Cons: None

I have a 54 gallon corner bowfront tank that is not drilled for a sump. I’ve been running a Fluval 406 canister filter for 1.5 years since the tank’s inception, but I grew tired of having to clean the canister twice per month to keep my water quality high. Finally upgraded to the CPR CS90 Overflow and its awesome! Having the security of the continuous siphon makes me feel much better if we experience a power outage. Partnered this overflow with a Trigger Systems Sapphire Cube Sump with an Ecotech Vectra S1 as my return pump. System is working flawlessly! I highly recommend ordering the lid for the overflow box to reduce noise and salt creep. Super happy with CPR’s product. I have their hang-on-back AquaFuge2 Refugium. Quality company!

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Reviewed on
September 08, 2017

No, I would not recommend this.

Bad product improvement

Pros: none over previous model

Cons: slotted intake edge no bueno

The old model was much better without the slotted intake edge. The slots tend to clog with tank gunk and need to be cleaned all the time. The clogs restrict the water flow into the box. Engineering gone wrong

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Reviewed on
May 11, 2017

Yes, I would recommend this.


Pros: Everything

Cons: Nothing

This is an amazing product...great quality and wont loose siphon when you use the aqualifter....also on even with the aqualifter off...it still keeps siphon. Much better then other overflows.

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Reviewed on
February 10, 2017

Yes, I would recommend this.

Great product

Been using a CPR 90 for over 10 years on a reef. I'm extremely happy w/ the product. It's solidly built and last.

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