Live Chat Support
    Free Shipping On $175+
  • FREE Shipping On $175+
  • 14-Day Low Price Guarantee
  • 14-Day Low Price Guarantee
  • Same Day Shipping
  • Same Day Shipping
FREE Shipping on
Orders Over $175
Standard ground shipping (1-7 business days) starts at a low $5.99 and most orders over $175 ship FREE. Learn More
If you find a product we sell for a lower price at another online store, we will match their price—today and up to 14 days after you've purchased the item! Learn More
Same Day Shipping
We promise to ship your order as fast as humanly possible. In fact, 99% of orders placed before 6 pm EST ship the same day! Learn More

Overflow Boxes

CPR Overflow Boxes
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.
Tom Aquatics Pro Series Surface Skimmer Overflow Box
The Patented Surface Skimmer Overflow efficiently skims the surface water of the aquarium, removing dissolved organics and other waste material.
CPR RSS Overflow Box Retrofit Surface Skimmer
The RSS Overflow is a simple way to add a surface skimmer to any tank with a bulkhead mounted overflow. Users can choose between the regular unit or the DX model depending on the installation method they desire.
External overflow boxes drain water from a display tank into a sump or wet/dry filter when paired with an aquarium that did not come pre-drilled.

We carry several sizes to assure you’ll we’ve got the right overflow box for your flow rate.

Don’t forget to add an Aqua Lifter Vacuum pump or a powerhead with venturi capability (Maxi-Jet powerheads are a customer favorite) to ensure your overflow box maintains the proper siphon and restarts automatically following a power outage.

Built-in overflows are the most efficient way to drain aquarium water into a filter. If your aquarium does not have a built-in overflow, an overflow box is the best alternative for getting tank water into a filter system without spending a fortune on tank modifications. They also skim up to six times more water than units with tubes.

Overflows/Pre-filter Advantages:
  • Easily adjust aquarium water level to precisely the right amount for your setup
  • Plastic screens help prevent fish loss
  • Quiet operation

This item is temporarily unavailable but will be back in stock soon.

Item #
Click the Add To Cart button below if you'd like to reserve this item today. Any other items included in your order will be immediately processed and shipped. We will ship this item separately as soon as it arrives. We will not charge you for this item until it ships and you will incur no additional shipping charges.

Enter your email address in the field below and click the Notify Me button if you'd like us to send you an email when this item becomes available. Although you will be immediately notified when we have stock on hand, we will not reserve any units for you; you must return to our website and place an order.

Your Email:
Just enter your email address below and we'll let you know when the product you are looking for becomes available!

Item Code:
Your Email:
Email Specials
Subscribe to our newsletter feed.
Newsletter Tips & Tricks! New Products!
Discounts & Promos!
Nov 24, 2014
"Shipping was easy and quick; customer service was great."

Nov 23, 2014
"Huge fan of the early online Black Friday deals!! Makes getting large purchases like a protein skimmer much more reasonable."

Nov 22, 2014
"Always love the service and speed of receiving my product."

Save Money Get our best deals, product how-tos and expert tips delivered weekly to your inbox.