Are Sump Tanks Needed in Aquaponics? (Best Guide)

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In a simple aquaponics system design, fish tank water is pumped out into the grow beds to provide nutrients to the plants. The water is then filtered by the plants, before ultimately flowing right back into the tanks. Ideally, as the cycle continues, the water supply for the entire system should remain the same. However, aquaponics practitioners often find themselves wanting to increase their plant production by adding more grow beds. The problem is that by expanding the grow bed capacity, more water is used, which leads to lower water levels in the fish tanks.

One of the keys to maintaining a thriving aquaponics ecosystem is making sure your fish are healthy and happy. Low water levels do not help accomplish either of those things. Thus, the question often arises, are sump tanks needed in aquaponics? Is this the solution to increase crop production without adding a new fish tank?

Sump tanks are not a requirement for all aquaponics systems. But it helps in maintaining the right water levels of your fish tank. By adding a sump tank, you create a better aquatic environment for the livestock. Plus, you get to maximize and reuse all the runoff from the system. Using one should be based on your fish tank to grow bed ratio. 

If this sounds confusing don’t worry. In this article, we will share how aquaponic sump tanks work, how to choose the right size and design for your system, and where to find the best pumps. Similarly, we will provide the basic costs for adding it, and how much electricity it consumes. 

What is a Sump Tank?

A sump tank is an accessory added by aquaponics practitioners with at least 1:2 fish tank to grow bed ratio. Since the fish tank is not proportional to the grow bed, providing water to multiple grow beds could result in low water levels. And this could be detrimental to the fish. What a sump tank does is that it serves as the collector of all the water drained in grow beds where it pumps it back to the fish tank. Therefore, maintaining the right water levels for the fish. 

Apart from providing consistent water levels for the fish, it also improves aeration. This increases the dissolved oxygen level for your livestock. 

Aquaponics Sump Tank Size

As a generic rule of thumb, your sump tank size must hold or handle the grow beds’ total volume of water. Here’s a simple step-by-step process to identify the right sump tank size for your aquaponics system.  

Step 1. The first step is to add the total volume of water from the grow beds.

Step 2. Deduct the displacement effect of the grow media from the total volume of the grow beds. For Hydroton, which is a popular option for grow media, 55% of water is displaced.  

Step 3. Identify the volume of water needed to cover the sump pump in your tank. This is crucial to avoid overheating, which can cause further issues. 

Step 4.  Add the result from Step 2 and Step 3 to get the total volume capacity required from your sump tank.  

Aquaponics Sump Tank Design

There are two main sump tank designs for an aquaponics system. These are the CHIFT PIST/ CHOP and the CHOP 2. Let us briefly explain each design to identify what will work best for your needs. We also added a table for easier comparison.     

CHIFT PIST/ CHOP 

This stands for Constant Height in Fish Tank – Pump In the Sump Tank, Constant Height One Pump.  While it may sound intimidating, this design is straightforward. 

The way that this system works is that the water from the fish tank overflows to the grow beds. The water is drained to the sump tank where a pump pushes or ‘pumps’ back the water to the fish tank.  

The challenge here is that you have to place the sump tank at the lowest point of your system. If possible, elevate your grow bed and fish tank or dig a pit to accommodate this design. Also, make sure that your water level in the sump tank is high enough to cover the pump.    

CHOP 2  

With this design, the sump tank provides water to both the fish tank and the grow beds using a dual loop system. The grow beds use an auto-siphon, and the fish tank uses gravity feed overflow. The advantage of using this system is that it is easier to add more grow beds in the future. This is as long as the tank can hold the total volume and uses a reliable pump.        

Sump Tank Design	Advantage/s	Disadvantage/s
CHIFT PIST/ CHOP	Easier to set up	The tank must always be at the lowest point of your system  Regular monitoring of water level in the sump tank is required
CHOP 2	Provides water to both grow bed and fish tank   Easier to add more grow beds in the future	Additional materials are needed to complete the design  The filtered water from the grow bed is mixed with the water from the fish tank

If this is your first time using sump tanks, we recommend the CHIFT PIST/CHOP option due to the simplicity of the design. And to avoid overheating of your sump pump, target a model that has a vertical float switch. This triggers the pump when it reaches a certain level and automatically turns on and off.     

Aquaponics Sump Tank Cost  

The cost of building an aquaponics sump tank depends on the materials, including the tank itself, the sump pump, the clear tubing, and the drain pipes. You also need to consider labor costs if you will have a professional build one for you. To give you an idea, we’ve listed the materials you may need for your aquaponics sump tank and links to Amazon where you can check the latest prices.  

Materials for Building an Aquaponics Sump Tank 

MATERIALS AMAZON LINKS PVC Pipes  (1-¼” per ft) Click Here To Shop PVC Clear Tubing  (100 feet) Click Here To Shop IBC (275 Gallons) Click Here To Shop Sump Pump (⅓ hp) Click Here To Shop

*Note that the items above cover only the basic materials to build a sump tank and not the entire cost of an aquaponics system.    

How Much Electricity Do Aquaponics Sump Tanks Use? 

Many aquaponic growers are also concerned about the electric consumption of sump tanks. This depends on how large your system is and the pump you are using. To have an idea, we created a table below.  

Sump Pump hp	Estimated Watts (Running)
⅓ hp	250
½ hp	500
1 hp	750

These are just estimated figures. It may vary depending on the model of your sump pump and your overall usage.  

Where to Buy an Aquaponics Sump Tank and Pump 

An IBC is a great material for a sump tank. However, you can use more affordable options such as a wide tub or a repurposed drum cut into half. These are readily available anywhere. Just make sure that you have calculated the water volume that your tank should handle. Apart from the tank where the water will be collected, your sump pump plays a huge role.  And that’s why we took the liberty of finding the best ones in the market. 

MATERIALS AMAZON LINKS Superior Pump 91570 ½ HP Thermoplastic Submersible Utility Pump with 10-Foot Cord Click Here To Shop DEKO Sump Pump 1HP 3302GPH 750W Click Here To Shop FLUENTPOWER Electric Submersible Pump 1/3HP with Max Flow 2100 GPH Click Here To Shop

Before getting your sump tank pump, check its capacity to ensure that it will work best for your system. In addition, always check the warranty from the manufacturer. 

Conclusion: Are Sump Tanks Needed in Aquaponics? 

Sump tanks are not a requirement for an aquaponics system. However, it could help maximize efficiency, water consumption, and improve the environment for your fish. They can also assist in avoiding certain types of fish diseases as well. A sump tank is ideal if you want to add more grow beds or stretch the aquaponics system to a 1:2 or 1:3 ratio.   

The most important factors to consider would be your tank’s size and the capacity of your sump pump. Feel free to use our recommendations above if you want to add a sump tank to your aquaponics system.