A sump is simply a water containment area that is set below an aquarium for placing the equipment, providing different types of water for filtration to for the aquarium, adding top-off water into the tank as well as performing many other maintenance tasks. The sump provides you with enhanced control over your fish only or reef display tank. Some aquariums have sumps while others don’t have and it all depends on you to decide on whether to install one or not. The benefits that come with installation a sump exceed the risks by far and you will see most of the successful aquariums utilizing a sump in their operation.
Besides the sump, some also utilize the refugium as well. Having a sump increases the total volume of water in your aquarium. This helps in diluting accumulated pollutants in the water and helps avoid in most of the issues faced by sumps without a sump. The sump also skims the surface and thus assures you no surface scum and that your water will be crystal clear. In addition to this, it lowers the temperatures and is used for hiding the equipment such as protein skimmers, heaters, grounding probes, monitoring problems, etc…
Most importantly, utilizing a sump in your aquarium assures you consistent water level as the display tank is capable of maintaining the same level of water at all times. This is also a safe place for pouring in additives. By adding chemicals in your sump or new water, it enhances it to mix well before it has entered the display tank. The sump also promotes increased circulation. Increased oxygenation is yet another benefit that comes with the sum. This is because as water is drained into the sump, the air gets to mix with the water which allows beneficial gas exchange, addition of fresh oxygen in the water and releasing CO2.
When utilized, water will be draining from your display tank right to the sump container that is located beneath the aquarium. A return pump is used for pushing back the water to the water to the tank. This either runs externally or is submerged into the sump. When run externally, bulkheads and plumbing will be used and this helps avoid addition of heat into the water. Now, as the water slowly rises at the display tank, the water will flow into your overflow chamber and it is drained back to the sump. The cycle is constant and its main goal is ensuring that as much water is pumped depending on how much the tank is able to drain.