The clean sump setup inside one of our employee's aquarium stands.

To sump, or not to sump? That is the question pondered by many aquarium hobbyists.

With all the useful gear available for reef tanks, one of the most beneficial pieces of equipment is sometimes overlooked because it is usually kept hidden inside the aquarium stand.

The benefits a sump offers are numerous, although it is important to note that setting up a sump often requires as much planning and consideration as your display tank. Ensuring there is enough room for equipment to be placed—both from the start and add-ons down the road—as well as having proper baffle sizes, spacing and water depth, are crucial.

See more of Brad's amazingly clean stand, sump and 110-gallon reef tank.

Before we dive deeper, if you are not sure what a sump is or want to learn how to plumb a sump into your aquarium system, please take a look at this article to get you up to speed.

Now, let’s find out if a sump is right for you.

Surprisingly, this is an easy question to answer. Most aquarium systems can utilize a sump provided you have the space to accommodate one. Tanks that come pre-drilled with an overflow are your best choice.

However, even if your tank did not come pre-drilled you still have a couple of options to consider. You can drill the tank yourself (there are countless demonstration videos on YouTube you can reference) or you can install an overflow box to bring water from your display tank to the sump.

How big should your sump be relative to your display tank?

In my opinion, a sump can never be too big. In fact, the bigger the better, in my experience. When I first got into reefing, I recall seeing Julian Sprung’s 15-gallon reef tank with a 60-gallon sump (refugium, actually) in a few magazines and in one of his books.

But you can go too small. A 10-gallon sump on a 55-gallon aquarium is unlikely to provide the space you need for equipment. It is also a good idea to have a sump large enough to accommodate some extra water in the event your return pump fails and water is back-siphoned from your display tank into the sump.

 Learn more about Leo's sump and the equipment he uses to keep his reef healthy.

A sump discussion would not be complete without covering the major pros and cons of running one, so let’s dig in to help determine if a sump is right for you.

The Pros of Running a Sump

  • Increased water volume. Greater water volume generally provides a more stable and forgiving environment for livestock, which are always good for a reef aquarium.
  • Hide aquarium equipment. Not having to place your heater, probes, protein skimmer and other equipment in (or hanging-on) your aquarium will make your display tank look cleaner and more natural.
  • More protein skimmer options. The number of in-tank and hang-on back protein skimmers available is limited; in-sump skimmer options are plentiful.
  • Sumps are great vessels for dosing supplements. This can help prevent high concentrations of chemicals from coming into contact with your prized coral collection.
  • Constant water level in your display tank. When you have a sump, water lost from evaporation will only drop the water level inside the sump and not in your display tank.
  • Automatic top-off systems are more reliable. Auto top-offs tend to work best in sumps.
  • More filtration options. With more space to work with, you can strengthen your filtration system by utilizing filter socks, sponges, a refugium, protein skimmer and/or media reactor.

See more of Charles' 180-gallon reef aquarium and sump setup.

The Cons of Running a Sump

  • Your aquarium may be louder. An increase in noise caused by water splashing into the sump or overflow is possible. Additional equipment you add to augment your filtration system may also increase noise.
  • Possible flooding if installed incorrectly or piping detaches. When the return pump is de-energized, the water level in your display tank will drop to overflow levels and water inside tubing will drain and fill the sump.  If the “dry” area of the sump (the area between the running water level and the rim of the sump) is not large enough, this could cause excess water to overflow the rim of the sump.
  • You will spend more money. There are some increased costs to using a sump, especially if you have one custom made (although it is well worth the cost, in my opinion).
  • Not all sump setups are created equal. If your aquarium is not drilled for a sump, you will need an external overflow box. While certainly a great substitution for a drilled tank, they are not as ideal as a built-in overflow. There is a higher chance of flooding due to failure in comparison.

The 34-gallon NextReef NRS-36 Aquarium Sump available now at Marine Depot.

At this point in my hobby career, I would not even consider setting up a reef tank without a sump unless it was an all-in-one (AIO) style aquarium. The benefits of a sump far outweigh the risks.

If you are planning a new reef aquarium, spend a little extra to get a tank with a built-in overflow. If you already have an aquarium up and running and are looking to add a sump, consider using an overflow box or drill* your tank for an overflow. I am confident you will be happy with the results of adding a sump to your aquarium system.

*Before you begin drilling your aquarium, do some research. Get the proper tools. Note that tempered glass cannot be drilled. Please also take into consideration that drilling an aquarium generally voids any store or manufacturer warranty the tank may carry. Questions? Contact us!