The Benefits of an Aquarium Sump

An aquarium sump is a tank below your display tank that houses the equipment for the filtration system. This allows you to add mechanical, chemical and biological filtration without putting that gear in your display tank where it could be vulnerable to the fish and corals above. It also provides a place for you to grow macroalgae and a refuge for copepods and other tiny marine life. The benefits of a sump for your saltwater or freshwater aquarium are many, but the most important is that it increases the water volume in the system which helps to dilute toxins and improve stability.

The simplest way to think of an aquarium sump is a larger tank that sits under your display tank. The water from the aquarium runs down to the sump and then is pumped back up via the return pump. The pump is often a submersible model that sits inside the sump or it can be an external unit that pumps into the tank. The return pump can also house other equipment like heaters, protein skimmers and a refugium if you choose to add them.

Most sumps are divided up into sections using baffle plates. The first section is usually where the mechanical filtration takes place, either with filter wool, sponges or filter socks. The next chamber is where a protein skimmer can be added if you are running a saltwater aquarium and then a filter media reactor if you are running a freshwater aquarium. This is where your bacteria will thrive as they break down harmful ammonia and nitrite into less toxic nitrate.

The last chamber in the sump is often used for a microalgae tank or a refugium. This is where you can grow the macroalgae that will help to reduce nitrate and phosphate in your reef tank. The algae will then be consumed by the copepods and other small marine life that live in the refugium.

Another benefit of the sump is that it can be a good place for heaters and other equipment, like a powerhead, to hide from the fish and corals in your tank. This can save you some money on your energy bills and can make the filtration more efficient since you are not running the pump as much to heat or cool your tank.

There are a lot of different ways to design your aquarium sump to suit your needs and space. You can buy a pre-built acrylic sump or you can build one yourself from scratch, but all of them work on the same basic principle. The main aquarium water drains down to the sump through a weir and then into the overflow section where it gets pumped back up to the display tank. This keeps the water constantly flowing and makes sure that you never have a stagnant spot in your aquarium.