H2Overflow® Aquarium Overflow System

  • Works great with the Seamless Sump® system!
  • Maximize skimming and aeration capacity with a minimal footprint!
  • High capacity overflow volume with very little nose – up to 1200 GPH per overflow!
  • Easily accommodate higher capacity with additional overflows
  • Never see a water line in your aquarium – evaporation takes place in your sump system
  • Installs out of your line of sight – you won’t even see it at normal viewing height!
  • Displaces a fraction of the water as other overflow systems with more inches of skimming!
  • Molded design provides an easy to clean professional appearance
  • Can be installed in multiple positions to manipulate water circulation
  • Can be mounted out of the way of your reef lights to prevent shadowing
  • Easy installation, all that is needed is one hole drilled for a 1-1/2″ bulkhead
  • No reliance on silicone boxes or holes in the floor of your aquarium
  • Order the aquarium from us and we can drill holes for your overflow and returns for you!
  • Hole drilling kits available for easy installation on existing aquariums
  • Large skimming area minimizes risk of clogging/flooding compared to other overflow screens
  • Tapered screen design increases skimming rate automatically as flow rate increases

Order the H2Overflow® System

The H2Overflow® System

The H2Overflow® is an elegant, quiet, efficient way to get water from your aquarium to your sump tub, maintaining your aquarium water overflow. Works great with the Seamless Sump® system (or most other sump systems) and creates an out of sight minimal footprint.

Keeps Aquarium Water Line Above the Frame, Yet Below the Glass Lids

The unique design of the H2Overflow® aquarium overflow system design allows you to consistently maintain your water line above the bottom of the aquarium frame so you do not see the unsightly water line as water evaporates, yet below the glass lid so you do not have excessive evaporation. With most other aquarium water overflow systems, you have to choose one benefit or the other. With our aquarium overflow system, you have the advantage of both!

Water Line: Above Frame, Below Glass Lid

Allows abundant, efficient aeration without excessive evaporation!

Minimal Footprint with High Skimming Capacity

The H2Overflow® displaces a very small amount of water, yet has an extremely high skimming capacity. Each H2Overflow® has approximately 17.5 lineal inches of skimming! Compare this to a typical corner overflow which would have only 6-8 inches of skimming that can easily clog, displaces several gallons of water, is in plain sight, and requires holes in the floor of your tank!

17.5 Inches of Skimming!

Despite its small footprint, is very efficient at skimming large volumes of water without letting debris into your sump.

Automatically Increases Skimming Capacity with Higher Flow Rates

The H2Overflow® aquarium overflow system has a unique tapered design to the screen teeth that automatically allows an exponential amount of additional skimming capacity as the flow rate into the tank increases. A lower flow rate means smaller, finer streams of water flowing into the overflow. A higher flow rate makes exponentially larger, higher volumes of water flowing into the overflow. This means the same H2Overflow® will optimize the most efficient amount of aeration and quiet flow automatically, even when you have drastically different flow levels into the tank.

Tapered Teeth Screen Design

  • A key design feature
  • Optimizes flow and aeration
  • Minimizes risk of clogging

Aquarium Overflow System – Filters Small Particles, Yet Difficult to Clog

Our unique screen design lets larger and larger particles through as the flow rate into the tank increases or as the finer teeth become clogged with particles. The teeth are small enough to prevent even small food pellets from making their way to the sump. However, if particulates build up, eventually the teeth get further and further apart as the water level rises and you move up the overflow. This is an automatic built-in safeguard against clogging. In the event of a major amount of debris that may clog the teeth, the top screen has much larger holes that would allow larger debris and a lot of water capacity to flow; however, would not let debris through that is large enough to create a clog further down the sump system. Since most other overflows are hand manufactured one at a time with low tolerance tools like a table saw, this tapered screen design is nearly impossible to pull off with their designs. Our molded H2Overflow® aquarium water overflow system allows us to provide these types of important design nuances on every part that make a very big difference in performance while keeping the price affordable.

Aquarium Water Overflow – Positioning Options – Manipulate Water Flow or Avoid Lighting

Our unique H2Overflow® aquarium water overflow design lends itself to many different installation orientations. Whether your goal is to manipulate the circulation and direction of flow in your aquarium or to keep your overflow out of the way of your lights, your goal can easily be accomplished with this design. We do recommend gluing your assembly firmly together once you choose a position in order to reduce the risk of it accidentally separating which could cause excess water to drain into your sump and possibly cause a flood. Our standard setups come pre-glued in the “centered” position for this reason. Other pre-glued positions may be requested, or you can purchase your assembly dry fitted and glue into place yourself.

H2Overflow® Angles

H2Overflow® System – Rated in Excess of 1200 GPH!

The capacity of any aquarium overflow system will be relative to the specific circumstances of each individual setup. We have tested the H2Overflow® in conjunction with our most common Seamless Sump® configurations with as much as 2,500 GPH without experiencing a flood. However, the more you push the limits of your system the greater likelihood unforeseen events can cause problems. We have found through our testing that a single overflow can comfortably handle around 1200 GPH total overall flow rate and still allow your sump system to comfortably keep pace as well as not have too much noise and evaporation. The aquarium water overflow can technically probably handle quite a bit more capacity in a lot of circumstances, however, we like to consider a reasonable and practical safety factor in our ratings.

Only ONE Overflow Required for Aquariums up to 300 Gallons!

It is a generally accepted goal for most aquarium enthusiasts to try to cycle all the water in a well-balanced tank approximately 4 times per hour. When used in combination with our Seamless Sump® system, which is a very efficient biological filter, your flow and cycle rate requirements are not likely as high as the general rule of thumb. Even so, if a 4 times turnover per hour rate is desired, only one H2Overflow® would be needed for setups up to 300 gallons! However, this is only a rule of thumb for setups with 1200 GPH flow rates and less. Some setups prefer even higher flow rates or an even higher safety factor. If this is the case, additional overflows can easily be added to accommodate excess capacity.

Want More Capacity, Just add More H2Overflows®!

Additional overflows can easily be added to accommodate additional capacity. All that is required is drilling another hole for a 1-1/2″ bulkhead and adding another overflow assembly – no elaborate fabrication needed! Even aquariums 1,000+ gallons can utilize our H2Overflow® and Seamless Sump® systems, just keep adding overflows and sump tubs! Many configurations are available for different needs. Give us a call, our expert service technicians would be happy to help you configure your setup! We can drill holes in aquariums ordered from us. We also have do-it-yourself kits for drilling your own aquarium glass holes.

Easy to Clean, Removable Top Screen

The top screen is held firmly in place by gravity, water flow, and a molded recess in the aquarium water overflow. It is very easy to remove for cleaning purposes. The screen can also be held to the overflow with optional stainless-steel screws if more permanent fastening is desired or any other unusual application where you wish to place the overflow on its side. The design of this top screen also acts as a safeguard to prevent large debris, snails, and other unwanted specimens from entering your filter system.