How to Build a Fresh Water Aquarium Sump: A Step-by-Step Guide for Beginners

Do you want to build a freshwater aquarium that creates a beautiful and healthy environment for your fish? Then you need to invest in a sump system. While it may seem intimidating to tackle this project, building a freshwater aquarium sump is a straightforward process. Imagine that building a sump is like creating a home for your fish, with all the conveniences and safeguards that they need to thrive.

In this blog, we will guide you through the process of building a freshwater aquarium sump, providing all the information you need to get started. Whether you are an experienced aquarist or just starting, this guide will help you create the perfect sump for your aquarium.

Understanding the Purpose of a Sump

If you’re planning to build a freshwater aquarium sump, it’s important to understand the purpose of the sump. In short, a sump acts as an additional filtration system for your aquarium. It allows for more water volume and surface area for beneficial bacteria to thrive and remove toxins from the water.

Additionally, a sump can help hide equipment such as heaters and protein skimmers, creating a cleaner and more aesthetically pleasing aquarium. When building a sump, it’s important to consider the size of your aquarium and the amount of water being filtered through the system. By properly constructing a sump and incorporating it into your aquarium setup, you can ensure optimal filtration and overall health for your aquatic pets.

So if you’re looking to improve the quality of your aquarium water, consider building a freshwater aquarium sump as part of your filtration system.

What is a sump and why do you need one?

A sump is a submerged compartment located below the aquarium that houses equipment such as heaters, filters, and protein skimmers. The purpose of the sump is to provide additional water volume and a place for stocking and concealing equipment. The water in the display tank flows into the sump via an overflow system, where it is processed and then returned to the tank.

A sump also serves as a buffer to help stabilize water parameters such as temperature, salinity, pH, and oxygen levels. In addition, it provides a location for the addition of supplements, such as calcium and trace elements. Ultimately, having a sump can greatly enhance the health and longevity of your aquarium inhabitants by improving overall water quality and reducing strain on the main tank filtration system.

how to build an fresh water aquarium sump

Benefits of using a sump in freshwater aquariums

If you’re looking to take your freshwater aquarium setup to the next level, adding a sump is a great way to do it. So what exactly is a sump? Simply put, it’s an additional tank that sits below the main display tank and is connected to it via plumbing. This extra tank serves a number of purposes, including creating extra volume for your filtration system, providing a place for equipment like heaters and protein skimmers, and increasing the stability of water levels.

By adding a sump to your setup, you’ll be able to keep your tank cleaner and healthier by increasing the overall filtration capacity of your system. Plus, it can be a fun project to set up and customize to your specific needs. Whether you’re a seasoned aquarist or just starting out, using a sump in your freshwater aquarium is definitely worth considering.

Choosing the Right Materials

When building a fresh water aquarium sump, one of the most important steps is choosing the right materials. First and foremost, the body of the sump should be made of a non-toxic material such as glass or acrylic. It’s also important to select appropriate plumbing materials, such as PVC pipes and fittings, to ensure proper water flow and prevent leaks.

Additionally, choosing the right filter media is key to keeping your tank clean and healthy. Some popular options include mechanical filters such as sponge filters, biological filters like ceramic rings, and chemical filters like activated carbon. By selecting the right combination of materials, you can build a high-quality sump that will improve the overall health and clarity of your freshwater aquarium.

What materials are needed to build a sump?

When it comes to building a sump, choosing the right materials is crucial to ensure it functions effectively and lasts a long time. There are several materials to consider, such as aquarium silicone sealant, acrylic sheets, glass panels, and PVC pipes. Aquarium silicone sealant is a popular option for sealing all the joints of a sump, as it can handle constant exposure to water.

Acrylic sheets and glass panels are both durable and resistant to cracking, and they allow for clear visibility of the sump’s contents. PVC pipes are commonly used for plumbing purposes as they are easy to cut, connect and are resistant to corrosion. It’s important to choose materials that are suitable for not only your sump’s construction but also for the type of water it will hold.

Always choose high-quality materials to ensure a durable and effective sump that will maintain the health of your aquarium.

Recommended types of glass and acrylic

When it comes to choosing the right materials for your glass or acrylic, there are a few important things to consider. Firstly, you need to think about the type of project you are working on. For example, if you are building a fish tank, you would need to use a thicker and more durable acrylic than if you were simply creating a display case.

In general, glass is more scratch-resistant and easier to clean than acrylic, but it is also much heavier and more fragile. Acrylic is lighter and more shatter-resistant, which makes it a great option for projects that require a clear and durable material. Ultimately, the choice between glass and acrylic will depend on your specific needs and the demands of your project.

By carefully considering these factors, you can choose the right materials that will help you achieve the best possible results.

Designing the Sump

When it comes to building a fresh water aquarium sump, designing the sump is a crucial part of the process. The sump is essentially a container that sits below the main aquarium and acts as a filtration system for the water. To start, you’ll need to decide on the size and shape of the sump based on the size of your aquarium and the equipment you plan to use.

A good rule of thumb is to have at least 10-20% of the total water volume in the sump. Next, you’ll want to consider the placement of the different components such as the skimmer, heater, and return pump. It’s important to make sure these are in the right place for optimal function and accessibility.

Lastly, think about the overall design of the sump and how it will fit into your aquatic setup. Will it be hidden or on display? Will it be easy to maintain and clean? By taking these factors into consideration, you can build a sump that is both functional and aesthetically pleasing.

Determining the size and placement of the sump

Designing the sump for your aquarium is a crucial step in setting up a healthy and thriving underwater environment for your fish. One important aspect to consider is the size and placement of the sump. This will depend on the size of your aquarium, the number of fish you have, and the space available for the sump.

Generally, larger aquariums require larger sumps to accommodate the increased water volume. The sump should also be placed below the main tank, allowing for an efficient gravity-based flow of water. When designing the sump, consider adding features such as filter media, protein skimmers, and heaters to help maintain water quality and temperature.

Remember to choose materials that are sturdy and reliable, and make sure all plumbing connections are secure to prevent leaks. With careful planning and design, your sump can help provide a healthy and happy home for your aquatic pets.

Creating a basic blueprint for the sump

When designing a sump for your aquarium, it’s important to first determine the size and needs of your aquarium. The sump should be able to accommodate the amount of water in your aquarium and hold all necessary equipment, such as a protein skimmer, filter media, and a return pump. A basic blueprint for the sump can be created by sketching out the dimensions and compartments needed, such as a filter sock holder, a protein skimmer chamber, and a return pump area.

It’s also important to consider the plumbing and overflow system, ensuring that the water flows smoothly and efficiently. With the right design and planning, your sump can play a crucial role in maintaining a healthy and thriving aquarium ecosystem.

Building the Sump

If you’re setting up a freshwater aquarium, building a sump is a great idea. It helps to increase water volume and filtration capacity, providing a more stable environment for your fish and other aquatic life. To build your sump, you’ll need a few basic components, including a tank or container to hold the sump, a pump to move water to and from the sump, and various filtration media like foam pads, bio-balls, and charcoal.

Start by selecting the appropriate size container for your sump based on the size of your main tank. Then, install your pump so it can move water from your main tank to the sump and back again. Create a series of filter chambers using the filtration media, making sure to calculate flow rates to ensure efficient water circulation.

Once you’ve got your sump set up and running, you can enjoy the benefits of improved water quality in your aquarium. Overall, building a sump is a great DIY project that can save you money while helping you create a better environment for your aquatic pets.

Step-by-step instructions for constructing the sump

When it comes to constructing a sump system, it’s important to take a step-by-step approach to ensure everything is in place. To start, you’ll need an appropriately sized tank with baffles that keep water flowing smoothly. Then, attach a pump to the tank to move water from the main tank into the sump.

In the sump, you’ll want to include mechanical filtration like filter pads or sponges, as well as biological filtration like live rock or bio balls. Supplement with a protein skimmer to remove excess organic matter, and a heater to maintain a consistent temperature. Once everything is in place, test the system for leaks and make any necessary adjustments.

With these steps, you’ll be well on your way to building a successful sump system for your aquarium.

Tips for ensuring a watertight seal

When building a sump, it’s crucial to ensure that the seal is watertight to prevent any leaks or floods. One of the most effective ways to achieve this is by using silicone sealant, which provides excellent adhesion and flexibility. Before applying the silicone, it’s important to clean and dry the surface thoroughly to remove any dust, dirt, or debris.

Apply the silicone in a continuous line along the joints and seams, making sure to fill any gaps or crevices. Use a caulking gun for accuracy and precision, and smooth out the silicone with a tool or your finger to create a neat finish. Remember to give the silicone enough time to dry and cure as per the manufacturer’s instructions before filling the sump with water.

By taking these simple steps, you can ensure that your sump is well-sealed and ready for use.

Installing the Sump

If you’re looking to build a fresh water aquarium sump, installing it can be a bit intimidating, but it’s not as complicated as it may seem. First, locate an area beneath the tank where the sump can be placed. Once you’ve found a suitable spot, it’s time to drill holes in the tank for the sump’s drain and return lines.

Be sure to measure and mark the drilling points accurately to avoid any mistakes. Before drilling, make sure the tank is completely drained and use a diamond hole saw to drill the holes. Once the holes are drilled, it’s time to install a bulkhead fitting on the inside of the tank to connect the sump’s plumbing.

After the bulkhead fitting is securely in place, the sump can be carefully placed beneath the tank. Finally, connect the sump to the tank’s plumbing, fill the tank with water and check for any leaks. With a little patience and attention to detail, you’ll have a fully functional sump that will aid in maintaining a healthy and thriving aquarium.

Connecting the sump to the aquarium

Installing the sump is a crucial step when setting up an aquarium. To connect the sump to the aquarium, you need to consider a few things. Firstly, ensure that the sump’s water level is lower than the aquarium’s water level.

This way, the water will flow from the aquarium into the sump and back again. A ball valve or gate valve should be installed in the plumbing to control the water flow. Secondly, use flexible PVC piping to connect the sump to the aquarium’s overflow box or bulkhead.

Ensure that the PVC piping is properly sealed with PVC glue and securely fastened with hose clamps. Lastly, it’s essential to properly position the sump beneath the aquarium stand, ensuring it is level and stable. With these steps complete, you can sit back and admire your newly installed sump, knowing that it will help keep your aquarium water clean and healthy for years to come.

Proper placement and maintenance of the sump

Installing the sump is a crucial part of maintaining a healthy aquarium environment. First, you must choose the right location for the sump. It should be easily accessible and out of harm’s way from pets or children.

Additionally, it should be placed lower than the main tank, allowing for gravity to pull water down into the sump. When it comes to the installation process, it’s important to start with a well-supported stand that can handle the weight of the sump and its contents. The sump should also be level, and all connections should be secured tightly to avoid leaks.

Don’t forget to add the necessary equipment to the sump, such as a protein skimmer and return pump. Keeping up with regular maintenance of the sump, such as cleaning the filter socks and regular water changes, will ensure it continues to function properly. By installing and maintaining your sump correctly, your aquarium will thrive, and your fish and other aquatic life will be healthy and happy.


Building an aquarium sump for your fresh water tank may seem like a daunting task, but with the right tools and a bit of know-how, it can be a breeze. From selecting the right materials to designing an efficient layout, building an aquarium sump allows you to customize your filtration system to give your fish and plants the best habitat possible. And with a little creativity, you can even incorporate unique features and decorations, making your sump both functional and beautiful.

So dive into the world of aquarium sumps and discover the endless possibilities that await you – your fish will thank you for it!”


What is a freshwater aquarium sump?
A freshwater aquarium sump is a designated, separate compartment, usually constructed below the main tank, which contains additional equipment and provides filtration and circulation for the main tank.

Why should I use a freshwater aquarium sump?
A freshwater aquarium sump allows for additional water volume, which helps stabilize the main tank pH levels and provides better filtration and circulation. It can also be used to hide equipment clutter and increase the overall water capacity of your system.

How do I build a freshwater aquarium sump?
The process of building a freshwater aquarium sump involves determining the size and shape, selecting the right materials, drilling and plumbing, and setting up the filtration equipment. Follow a detailed guide or seek assistance from a professional for best results.

What is the ideal size for a freshwater aquarium sump?
The ideal size for a freshwater aquarium sump depends on several factors, including the size of the main tank, the desired water volume, and the type and number of equipment that will be housed in the sump. A general rule is that the sump volume should be one-third to one-half of the main tank volume.

What equipment do I need for a freshwater aquarium sump?
The equipment needed for a freshwater aquarium sump varies depending on the specific needs of the main tank, but typically includes a filter sock, a protein skimmer, a return pump, and possibly other equipment such as heaters, reactors, and media filters.

How often should I clean my freshwater aquarium sump?
Cleaning frequency for a freshwater aquarium sump depends on tank size, bio-load, and the type of equipment being used. Generally, a sump should be cleaned every three to six months. The filter sock should be changed out weekly, and other filter media should be rinsed as needed.

Can I use a freshwater aquarium sump with a planted tank?
Yes, a freshwater aquarium sump can be used with a planted tank. The sump can help provide better water flow and filtration, which can benefit the plant growth. However, the biological filtration should be designed to avoid removing necessary nutrients, and the lighting should be tailored to the specific needs of the plants.