Overflow boxes are one of the most iconic, aquarium-hobby specific devices which has been helping turbo-charge reef aquariums for decades. However, after years of stagnation we’re starting to see a big shift in the way overflow boxes are made, and what they do for our aquarium systems.
So called for the way that a U-shaped tube siphons water over the edge of the aquarium, overflow boxes are the go-to way to add an external sump to undrilled glass aquariums. However the new, slim-profile ‘overflow boxes’ are really more like very specialized drain designs, with no siphon but instead offer a sophisticated way to allow water to drain down into a sump beneath the aquarium.
A number of aquarium companies have made a concentrated effort to develop this new generation of overflow boxes, each offering their own set of features, build-quality and value. We review the three companies making a big push into this new segment of the aquarium hobby and try to highlight how each one is different.
The Reef Savvy Ghost Overflow is the original, dedicated slender overflow device which arguably kicked off the new momentum in this product space. The Ghost Overflow arguably features the highest level of craftsmanship of any of these slim overflow boxes, all being hand made from acrylic with very tight quality control.
The Ghost overflow has an easily accessible and removable comb screen to make it easier to clean this important part of the draining process. The internal box is very thin at 1.25 inches wide, but there’s plenty of room in the three inch wide external box to install your own plumbing tricks for quieting the sound of the draining water.
The Reef Savvy Ghost Overflow is rated for up to 2,000 gallons per hour and costs $250.
The Synergy Reef Shadow Overflow is the second oldest of the slim overflow and it’s got a lot going for it as well. Better known for creating bespoke, custom sumps with fluorescent accents, Reef Synergy was really promoting the Shadow Overflow at their MACNA booth with this being the only product on display.
The Shadow Overflow from Synergy Reef has completely different construction from the Ghost and others with recently developed tooling for molded parts. The internal box is made from molded ABS plastic and is also fairly thin at just 1.35 inches wide, with a spacious external box which includes basic siphon-silencing parts for a quiet drain.
The external part of the Shadow Overflow is a little bit flimsy without its cover to hold it together, but once all assembled it shouldn’t have to endure any stresses anyway. The Shadow Overflow from Synergy Reef Systems is rated for up to 1,500 gallons per hour and costs $199.
The Eshopps Eclipse Overflow is the newest addition to this product category, and is also the cheapest. Eshopps has been making true overflow boxes of various types for many years now, so it was a logical choice for them to try and expand the slim overflow drain box market.
Like all Eshopps products, the Eclipse Overflow is made of all acrylic parts, the thick solid kind which we come to expect from the manufacturer. In contrast to the Ghost and Shadow boxes, the Eclipse actually comes in three sizes, so you can get that stealthy drain box look to suit a range of tank sizes.
Eshopps’ Eclipse Overflow Boxes have equally thin internal boxes measuring at just 1.25 inches wide for all models. Instead of giving an actual flow rate through each of their models, Eshopps instead rates each Eclipse Overflow for a given tank size. The Eclipse S is rated for up to 75 gallons for $99, the Eclipse M is rated for up to 100 gallons for $109 and the biggest Eclipse L is rated for up to 150 gallon tank for $119.
