CPR Aquatics

Retrofit Overflow Box

Grouped product items
RSS05 Extra Small Overflow Box

SKU: 208179

In stock

Discontinued by Bulk Reef Supply

- +

An overflow box is a great way to keep the water level at a constant in your saltwater aquarium as well as increase the rate at which surface water, and the film and dust with it, is removed. CPR Aquatics are high quality, black acrylic and built in the USA. Install by using aquarium silicone. We suggest using a silicone color that matches the existing silicone in your tank.

Sizes Available

  • Extra Small - up to 250 GPH
  • Small - up to 500 GPH
  • Medium - up to 900 GPH
  • Large - up to 1200 GPH
  • Extra Large - up to 1600 GPH


Sizes Available

  • RSS05 - 6 3/8" L x 2 3/8" W x 3 5/8" H (Nano tank)
  • RSS07 - 5 1/4" L x 3 5/8" W x 5 1/4"H (Up to 60 gallon tank)
  • RSS12 - 7 1/4" L x 4" W x 5 1/4" H (Up to 120 gallon tank)
  • RSS18 - 12 1/2" L x 4" W x 5 1/4" H (Up to 200 gallon tank)
  • RSS24 - 18 5/8" x 4" W x 5 1/4" H (Up to 300 gallon tank)


When choosing an overflow we suggest using the largest overflow box that will fit your tank. It is impossible to oversize an overflow.

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Product Questions

I have a 40 breeder tank could I buy a bigger overflow like the rss12 or rss18 because on the review theres some complaints about water is to much
Question by: Dayton on Jun 21, 2016, 2:21 PM
Hey there!
As long as your overflow box is large enough to hold your drain pipe pick the largest which will allow for most room. The physical pipe diameter plays a larger role in restriction and as long as 1" pipe is used it can handle up to 600 GPH flow.
Answer by: Connor on Jun 21, 2016, 3:04 PM
so im gonna setup a new tank and want to run dual overflow on a 200 gallon setup, would i go with the 2 rss12's ?
Question by: josh on May 13, 2016, 8:51 PM
Great question! For enough room to work with plumbing fittings we definitely recommend the larger RSS 12's this will allow you to plumb any style system.
Answer by: Connor on May 19, 2016, 12:29 PM
What size goes with the 700 overflow lid?
Question by: Evan on Sep 5, 2014, 2:54 PM
Hi Evan,

The 700 lid measures 3"x3" and we do not currently stock an overflow box that size. Our smallest overflow box is the RSS05. Its measurements are - 6 3/8" L x 2 3/8" W x 3 5/8" H. The RSS05DX is very similar but it has a back on the overflox - 6 3/8" L x 2 5/8" W x 3 5/8" H.


I hope this helps.
Have a great day :)
Answer by: Bulk Reef Supply on Sep 5, 2014, 2:54 PM