Simply put, a sump is a supplementary tank that collects water to be filtered and hides all the ugly stuff you don’t want in your main tank such as a calcium reactor, protein skimmer, heater, or waste collector. The sump itself is not a filter, but it houses all the filtration systems you have installed. The sump does a lot more than change the look of your tank, it also adds an extra layer of control that affects the chemistry of your tank. Most beginners are worried that adding a sump adds an additional level of difficulty to the tank, but the benefits of add a sump far outweigh the negatives.
The number one benefit to adding a sump to your aquarium is for the storage it provides in housing some of the more unsightly aspects of your tank. Keeping your tank clutter free is not only aesthetically pleasing, but it also keeps helps in keeping your tank clean and keeping your inhabitants safe! Some fish can find themselves in some tricky situations such as getting lodged behind heaters causing them great harm. Another benefit is the task of cleaning your tank becomes much easier when there are fewer obstacles within it and is less disruption for your tank inhabitants. Lastly, another huge benefit of having a sump is the added water volume to your tank. More water is less maintenance and gives you more control over the stability of your water chemistry and requires fewer water changes.
Due to evaporation your display tank’s water level falls. Without a sump you are often topping off your display tank with freshwater to maintain a constant water level, as well as safe salinity for your inhabitants. A benefit to a sump is that your display tank will have a constant water level and the evaporation happens to the sump. So be sure to keep an eye on your sump’s water level. The water from your sump is always moving, keeping your surface water clean while also creating a flow that would normally require a wavemaker or some sort of surface pump. Having a sump also gives you the ability to run a refugium which adds another level of control to your tank and can even give you the ability to experiment with unconventional methods of reefing or fishkeeping.
Sumps require your tank to have an overflow which drains water that reaches the point of “overflowing.” This process is what keeps the top of the water clean. The water that flows down to the sump “aerates” and introduces more oxygen to the water. An overflow can either be an external “hang on” overflow or drilled into the tank. The hang on overflows are a perfect solution if you do not have access or are unable to drill your tank. The drilled overflows can either be DIY or you can purchase a tank that is pre-drilled, these are called “reef-ready tanks.” Reef-ready tanks are a perfect solution for running a sump straight out of the box and they often look amazing!
The sump itself requires space beneath your tank for the water to flow to. Tank cabinets are built with sump space in mind, these are perfect solutions for sump storage. You can also have your sump in a different room than your tank if you are tight on space or prefer something other than a cabinet for your tank to rest. Doing this requires a stronger return pump, skills to plumb the tubing, and space for your controllers. Having your sump in a separate location is an extreme option that should only be considered by experienced reefers!
Instead of listing out any negatives I would touch on making sure the sump is an appropriate size for the tank, keeping the sump water level topped off, and using a float switch. I added noise and space issues into another paragraph. While sumps overall add a lot of benefits to your aquarium there are a few things to be considered. While not typical, sumps can fail resulting your tank overflowing and potentially harming your inhabitants, This is usually caused by your overflow pipes being clogged or other failures in the overflow. Hang on overflows can have a break in their siphoning process which can also cause the tank to overflow.
Sumps are not required for a beautiful or thriving tank but can do wonders for your aquarium. Increased water volume, housing for filtration equipment, higher oxygen levels, ease of water changes, and the added benefits of removing the “ugly” equipment from your tank makes having a sump an awesome addition to your tank! Check out our article on Refugiums and Protein Skimmers and please consider Triquatics for your filtration and sump needs!
Bigger is often better when it comes to sump sizing. Many will agree that the best setups will introduce more water volume to introduce stability to the system. Something else to consider is that you will need enough space in your sump in the event of a power outage, as the excess water in your display tank will overflow.
Pairing an auto top off system (ATO) with your tank gives you the added bonus of being able to maintain the correct water levels without the hassle of adding it manually.