Being new to the aquarium hobby is an exciting time! Learning about proper aquarium husbandry and exposing yourself to a variety of animals you probably didn't even know existed is fascinating. During all this excitement, it is easy to purchase a pre-fabricated all-in-one style aquarium or quickly throw together a simple tank with a canister filter and heater.

Although getting going in this fashion is fast and easy, these types of tanks can pose some frustrating problems in terms of aquarium filtration and maintenance. Taking the time to install a sump system instead can really make your life easy in terms of maintenance and allows for more effective filtration equipment to be hidden out of plain view.  

So get ready to toss out your old canister filter and open up your toolbox because we are going to show you just how easy and beneficial installing a sump and overflow can be!

A sump is simply another aquarium or container that can house your equipment and provide extra filtration for your tank. A sump is typically located below your display tank inside your aquarium stand. An overflow box is basically a box with a drain. It is required to draw water from your aquarium into the sump. Overflow boxes are available from a number of manufacturers and you will see a wide range of different shapes and styles.

Overflow Box

A hang-on overflow box is the easiest way to get water out of your tank and into a sump. These types of overflow boxes simply hang on the side or back of your aquarium and siphon water from your aquarium, over the edge, and down into your sump. They do not require any holes be drilled through the aquarium walls to function so they are the best choice for those looking to modify an existing aquarium or simply do not wish to drill holes in the aquarium wall. 

Internal overflow

Some aquariums, usually called "reef ready" aquariums, are pre-drilled by the manufacturer and already have an internal overflow box installed. Water simply flows into the overflow box and drains down into your sump. A return pump then returns water from your sump back into your aquarium. This is the best approach when purchasing a new tank because it is the cleanest and safest way to move water from your tank down into the sump. 

For the do-it-yourself (DIY) crowd, there are also overflow box retrofit kits which are pre-fabricated acrylic boxes that allow you to permanently install an internal overflow on your existing tank without the risk of losing a siphon. Essentially you drill the tank, install the overflow box, and you now have made a "reef ready" aquarium. These are more reliable than a hang-on style overflow and great for those who are upgrading an existing tank and confidence in their own DIY abilities. 

Trigger Sump

Once you have decided on the overflow box and drain, it is time to choose a sump. You basically have two options, build one yourself or purchase a pre-fabricated sump. Building a sump yourself will likely save you some money and allow you to customize the sump to your liking but does require some considerable effort. We have some great sump baffle kits from Fiji Cube that make the job easy. 

The easiest route is to purchase a pre-fabricated sump because it has everything you need, right out of the box, for connection to your overflow box. There is a wide variety of sumps available in a range of sizes. Do the research and decide on the various features that are important to you because you're going to find that price usually corresponds to the available features.  The most basic sumps are going to be much more affordable than your advanced complex sumps with all the bells and whistles. Just remember, so long as your using a sump, even the most basic, you're doing yourself a favor in terms of supplying more effective filtration to the aquarium. 

You want your sump to be at least 30% the size of your tank's total water volume. For example, a 100-gallon tank should have at least a 30-gallon sump. 

  1. Measure the available space you have to install the sump.
  2. Get the largest sump that will fit within that space.
  3. Keep in mind you have to install the sump so if it is going under your tank, be sure it fits through the openings in your tank stand.

Having a large sump increases your total water volume and allows you to easily install advanced filtration equipment without having to worry about space.  Most experienced hobbyists will tell you, your sump can never be too big!