H2Overflow® Aquarium Overflow System

H2Overflow aquarium overflow system
  • Maximize skimming and aeration with a minimal footprint
  • High volume with little noise – up to 1200 GPH per overflow
  • Large skimming area minimizes clogging/flooding risk
  • Employ higher volume with additional overflows
  • Easy installation with one hole drilled for a 1-1/2″ bulkhead
  • Never see a water line in your aquarium
  • Installs out of your line of sight
  • Less water displacement, more inches of skimming
  • Install in multiple positions to adjust water circulation
  • Mount away from your reef lights to prevent shadowing
  • No reliance on silicone boxes or holes in the floor of your aquarium
  • Hole drilling kits available for existing aquariums
  • Tapered screen increases skimming rate as flow rate increases

Shop the full H2Overflow® System here!

The H2Overflow® System

The H2Overflow® is an efficient and quiet way to get water from your aquarium to your sump by maintaining the water overflow. This pairs perfectly with the Seamless Sump® system (and most other sumps) and is often out of sight in the aquarium.

Keeps Water Above the Frame but Below the Glass Lids

The unique design of the H2Overflow® aquarium overflow system gives you a consistent water level above the bottom of the aquarium frame, so you don’t see the unsightly water line as it evaporates. It also keeps water below the glass lid so there’s less evaporation.

With most aquarium water overflow systems, you have to choose one benefit or the other. With the H2Overflow, you have the advantage of both!

Minimal Footprint with High Skimming Capacity

The H2Overflow® displaces a very small amount of water at an extremely high skimming capacity. Each H2Overflow® has approximately 17.5 lineal inches of skimming!

Compare this to a typical corner overflow which has only 6-8 inches of skimming, clogs easily, displaces several gallons of water, is in plain sight, and requires holes in the floor of your tank.

Automatically Increase Skimming Capacity with Higher Flow Rates

The H2Overflow® aquarium overflow system has a tapered screen teeth design that allows an exponential amount of additional skimming capacity as the flow rate increases.

A low flow rate means smaller, finer streams of water are entering the overflow. A higher flow rate has larger, higher volumes of water flowing into the overflow. The H2Overflow® will optimize the most efficient amount of aeration and quiet flow automatically, even when you have drastically different flow levels in 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 proprietary screen design lets larger particles through as the flow rate into the tank increases, or as the finer teeth become clogged with particles.

The teeth are a built-in safeguard against clogging the system. They’re small enough to prevent food pellets from entering the sump, but if particulates build up, the teeth will get further apart as the water level rises and you move up the overflow. The top screen has larger holes that allow more debris and water to flow, but it’ll stop debris that is large enough to create a clog further down the sump system.

Since most other overflows are hand-made with low-tolerance tools like a table saw, this tapered design is a very unique and effective tool.

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

The H2Overflow® system lends itself to many installation orientations. Whether your goal is to manage the direction and circulation of the water, or to keep your overflow out of the way of your lights, you can accomplish it with this design.

We do recommend gluing your aquarium overflow firmly together once you choose a position. This reduces the risk of separation 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 it yourself.

H2Overflow® Angles

H2Overflow® System – Rated Over 1200 GPH!

The capacity of any aquarium overflow system will be relative to the specific circumstances of each setup. We’ve tested the H2Overflow® in our most common Seamless Sumps® (as much as 2,500 GPH) without experiencing a flood. However, the more you push the limits of your system, the greater the likelihood of problems occurring.

We’ve found through our testing that a single overflow can comfortably handle around 1200 GPH total overall flow rate, helping your sump keep pace. The aquarium water overflow can technically handle more capacity in a lot of circumstances, but we like to consider a reasonable and practical safety factor in our ratings.

Only ONE Overflow Required for Aquariums up to 300 Gallons!

It’s a generally accepted goal for most aquarium enthusiasts to cycle all the water in a well-balanced tank about 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. Even so, if a 4 times turnover per hour rate is desired, only one H2Overflow® is needed for setups up to 300 gallons!

However, this is only a rule of thumb for setups with 1200 GPH flow rates or less. Some setups need higher flow rates or higher safety measures. If this is the case, additional overflows can easily be added for extra capacity.

Want More Capacity, Just add More H2Overflows®!

Additional overflows can easily be added for additional capacity. All that is required is drilling another hole for a 1-1/2″ bulkhead and adding another overflow assembly! Even aquariums 1,000+ gallons can utilize our H2Overflow® and Seamless Sump®, just keep adding overflows and sump tubs!

Many configurations are available. Our expert technicians would be happy to help configure your setup! We can drill holes in aquariums ordered from us.

We also have DIY kits for drilling your own glass holes in your tank.

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. While it’s very easy to remove for cleaning purposes, the screen can also be held to the overflow with stainless-steel screws if more permanent fastening is desired or you wish to place the overflow on its side.

The top screen also acts as a safeguard to prevent large debris, snails, and other unwanted specimens from entering your filter system.