Do You Need A Sump For Saltwater Aquariums?

Are Sumps Required To Have A Saltwater Tank?

This is the ultimate guide to answering the following question. Do you need a sump for saltwater aquariums?

This is a question that is popular in the saltwater aquarium community. There are many opinions on the topic, and I believe there are huge benefits to incorporating a sump system on your tank.

In this comprehensive guide I will cover:

  • Are sumps required to have on a saltwater tank?
  • Purpose and benefits of a sump tank
  • How sumps work
  • What to put in your sump tank
  • How to choose the right size sump for your tank
  • Types of sumps
  • And much more

But the question is do you NEED a sump for a saltwater aquarium? The answer is no. It is absolutely possible to have a saltwater tank and even a reef tank without a sump. In fact, some hobbyists prefer to not have one.

Sump tanks have been on the aquarium scene for a while but have recently become the saltwater-tank fanatic’s passion and a point of deep interest and discussion across the aquarium community.

When I first started in the hobby, I didn’t pay much attention to sumps. I thought they were just a money grab and not really necessary. While that is kinda true, once I learned about them and understood the benefits, I now choose to use some sort of sump system on all my saltwater fish and reef tanks.

If you have been dazzled by some impressive sump setups or wondering if your own saltwater tank could benefit from one, the following post is for you. Let me show you more about these versatile systems for saltwater tank support.

Let’s look at some information regarding sumps and you can decide whether or not having one on your tank will be right for you.

Information about sumps for saltwater tanks

The sump tank is an additional containment unit that is set up alongside the saltwater display tank (the one everyone sees) and represents the functional side of the saltwater setup including the filtrations systems, heating elements and more.

Sometimes a fully-functional sump can be placed directly below the tank, which is most commonly used, but sophisticated setups for large display tanks can also take up an entire spare room if they contain the full-array of sump features, including equipment and possibly a sizable refugium as well.

As you will read in the following section, a sump provides a variety of special benefits to optimizing the conditions of your tank as well as facilitating regular maintenance and service. This can be accomplished with a very-costly and complex multi-chambered system if you choose to go that route, or by using simpler single-chamber sumps that perform the most basic functions.

As a matter of fact, once you understand the principles of a sump, it is fairly easy to design a solution that will fit the needs of your saltwater set up perfectly. While there are some ready-made options on the market and even All-In-One Sump Tank combos, many saltwater aficionados have designed their own highly successful sumps from an additional fish tank or even a Rubbermaid tote. My first sump was using a Rubbermaid!

Most recently for my 75-gallon reef tank, I went with the Eshopps RS-100 sump. Great system, easy to set up and has the proper compartments with a nice big filter sock!

Purpose and benefits of a sump tank

A sump is basically just another tank, whether it’s an aquarium or something else that holds water which normally sits below the main display tank. Its purpose is to hold equipment, filtration, and anything else you want to put in it that would be beneficial to your tank.

There are many benefits of having a sump tank with the main one being that it gives you more control over your system which directly affects the health of your tank.

Many hobbyists will argue whether a saltwater tank actually NEEDS a sump. In all truth, there are plenty of beautiful saltwater tanks that don’t use a sump.

Still, there are some important benefits that a sump provides for a saltwater tank.

  • They increase the total water volume of your system

Quite simply, if you are working with more water you will find it much easier to balance and maintain the conditions of your tank. If you have a 30-gallon tank and 20-gallon sump, you now have 50 gallons to work with. This means that your tank can support more fish for one, but it also means that internal temperatures are easier to regulate. It will also be easy to prevent and manage the buildup of phosphates and nitrates when using more water.

  • Lets you hide equipment – better organization

One of the downsides of a saltwater tank, in general, is the amount of equipment needed to keep them performing optimally. The sump allows all of these necessary functions to perform in a separate tank location. This means that all filtration systems, heaters, protein skimmers, and media reactors can be tucked away out of sight. Not only does this add to the visual value of your display tank, but even your sump set up can reflect the beauty of ingenuity and efficiency.

  • Allows for an auto top off system which helps maintain water level and stability

The water levels in your display tank will not change no matter how much water evaporates. The first place the reduced water will be noticed is in the sump itself and this is also where more water can be added without worrying about shocking the fish or other aquatic residents inside the display tank. Furthermore, there are automated top-off components that can be connected to your sump that observe and adjust salinity and water levels for you.

  • Stabilized PH levels

When the lights go off in the main tank photosynthesis stops and this means increased levels of CO2 in the water begin to create a more acidic atmosphere, which is not healthy for your fish. To keep pH levels at a balanced medium, you can have an algae compartment set up with live rock in your sump. When the lights go off in the display tank, the lights go on in this compartment and keep the photosynthesis process running and balancing the pH levels in the display tank –– this can also be done in the refugium.

  • Less equipment size limitations

Tanks that are larger than 150 gallons will be more difficult to run without a sump. This is simply because most of the heavy-duty equipment must be hung on the back of the tank. This larger equipment is especially unsightly and best kept in a separate tank dedicated to this purpose.

  • Food sources

Safely tucked away from the predatory marine life in your display tank, the sump makes a perfect breeding ground for minuscule marine folk to proliferate and thrive. As the populations increase many will find their way back to the display tank where they can integrate into the natural food chain. This is an especially good food source for inverts and corals as well as a variety of fish.

Other benefits include:

  • You can incorporate a refugium section into the sump
  • Increases gas exchange
  • Great place for dosing supplements
  • Better surface skimming
  • More flexible and increased filtration

Now that you have seen many of the benefits a sump can provide, let’s look at some of the potential downsides as there are some challenges that the presence of a sump places on your saltwater setup.

  • Pumps that feature a high flow rate can increase microbubbles in the display tank.
  • The addition of several pieces of equipment can increase the temperature levels of the water.
  • There will be increased costs of an additional return pump.
  • As you can imagine, this idea is not a space saver and requires plenty of room.
  • Should the power go out, you can expect the display tank to drain into the sump and you will need to consider proper leveling to avoid an overflow.

How do sumps work?

Sump systems work by having the water drain from the main display tank into the sump tank. The most effective way to do this is by having a reef ready aquarium with built-in overflows and plumbing. You can also consider drilling holes in your tank and use bulkheads and plumbing if your tank is able to be drilled. Not tempered glass. If that is not possible, you can use an external overflow box which creates a siphon and drains water to your sump.

After the water drains to your sump, it will need to be returned to the main tank by using a return pump. There are many different return pumps on the market today from a standard AC powered pump to a controllable DC pump where you can control the flow rate.

The water will be on a constant cycle of flowing to the sump and back to the display at a certain rate that you decide. Overflow boxes and return pumps have specific flow rates which will allow for a constant cycle of water through the sump tank. I mention in the article 13 common mistakes made with saltwater tanks, the importance of determining the size of your sump tank prior to adding it to your system.

What to put in a sump

One huge advantage that a sump tank provides, is the flexibility to add whatever you want in it. Depending on your tank needs, you can choose a variety of equipment, filtration materials, refugiums with lighting, and much more.

The common things to include in your sump tank include filter socks, filter pads, biological filtration media, macroalgae, protein skimmer, heaters, reactors, and return pump.

Sumps can also be divided into sections or chambers, and each section has a purpose. Most sumps will have the first section setup with filter socks where the display tank water will drain. Usually, this section is large enough for a protein skimmer to sit, but if not the next section will be fine.

Next will be a refugium section, where you can include macroalgae like cheatomorpha or mangroves which help with nutrient export.

After that will be a bubble trap and/or places for filter padding to provide mechanical filtration. Then ending with the final section where the water is returned to your tank via the return pump. You can also include an auto top off into this section.

The thing with sumps is that there are so many different types of uses and designs. I have seen some pretty amazing and technical sump systems that are worth a lot of money.

But sumps can be as simple or complicated as you need them to be. you may just want a bare tank with nothing in it but a heater. It’s up to you to design your sump system according to your tanks needs.

How to choose the right size sump for your tank

Perhaps the most important consideration will be the size of your sump in relation to the display tank. It needs to have the capacity to perform its various functions and also hold any water that will drain from the display tank and pipes in the event that your power goes out unexpectedly or your return pump was to fail.

This will be determined by the siphon break and needs to be calculated in advance.

When choosing the right size sump for your tank, try to use the largest tank that your budget and space in your stand will allow. A larger sump will provide you with additional water volume so if you have the option, always go with a larger sump versus a smaller one.

Try to aim for a sump tank that is at least 1/4 of the size of the main display tank. So if you have a 120-gallon tank, aim to have at least a 30-gallon sump.

Types of sumps

The common type of sump used in the aquarium hobby is one that sits underneath your tank usually in the stand area. You will need to make sure there is plenty of space in the stand to fit not only the sump but other equipment and plumbing.

If you don’t have the space underneath the tank, you can choose to use a hang on the back style refugium/sump. These basically serve the same purpose and any other sump, it’s just a lot smaller and hangs on the back of your tank as a filter would.

There are various styles of sumps on the market today. As mentioned earlier, it’s important to calculate the properly sized sump for your system. Also, determine the purpose of the sump before buying as this will help determine which style to get.

The Trigger Systems Crystal Sump is a great quality sump which includes all the basics and more. It includes the filter sock, refugium section, and a large return section to fit many sized return pumps. It has a nice design and built with custom acrylic which is lightweight and durable. It also sells at a great price which is a bonus!

If you are looking for something a bit more advanced with some added features, check out the Trigger Systems Sapphire sump. It has everything that the Crystal sump has, plus other bonuses that will increase the functionality and benefits of having a sump. It also has a very cool design that you will love! You can read more about this sump by clicking the link.

Sump alternatives

It may not be possible for everyone to have a sump. You may also decide that you just don’t want one, as I mentioned earlier sumps are not necessary. But they are very beneficial and helpful to your overall success of the tank as it matures. If running a sump is not in the plans for you, there are alternatives.

You could try a hang on back refugium, which I personally love to use. They are easily adaptable to your tank and you can still apply the functions of a sump into them.

You may also choose to use a basic aquarium filter to hold your filter padding and any other mechanical or biological filtration you like. If your goal is to have a place to run carbon, GFO, biopellets, you can try a media reactor.

Without having a sump, there are many options available for hang on the back reactors that work great. You can even have a macroalgae reactor and grow cheato just like you would in a refugium section of your sump.

Final Notes on Sumps for Saltwater Tanks –Are They Necessary?

There are alternatives to using a sump and many of these will work just fine for most saltwater tanks. While it is not imperative, the advantages of a sump for your saltwater tank set up are extensive. If you would like to know more about how to create the best sump, be sure to do your research and begin with a clear idea of what your display tank really needs in a sump.

Here is a great video from BRS Bulk Reef Supply explaining more details on sumps.

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