Pumps are the basis of every aquaponics system, and the right size pump will go a long way in making your system flawless.
Pumps primarily serve the purpose of constantly circulating water and nutrients required by the fish and plants in a system like aquaponics.
The fish and fish waste in a tank will excrete waste into the fish tank, the pump will push the waste water through biofilters to convert the fish waste into nutrients that can be absorbed and used in the system.
Then, the pump will pump the nutrient rich water back from the fish tank into the grow beds or towers.
Pumps can also raise the water level to the necessary height when needed, especially in aquaponics systems with vertical grow beds.
Moreover, some pumps are also aeration equipment adding oxygen to air-tight systems, for example, deep-water culture (DWC) systems.
Here are three pump examples for different size systems.
Vivosun 1600 GPH ( small-sized system )
Alpine 3100 GPH ( medium-sized system )
Anjon 4000 GPH ( large-size system )
What Are the Types of Pumps Used in Aquaponics Systems?
There are two main types of pumps used in aquaponics.
These are:
- Submersible pumps
- Inline pumps
Submersible Pump
A water pump like this is fully submersible in the fish tank and it pushes water out through a hose placed on the top of the pump.
It’s a great pump for hobbyists and aquaponics systems utilizing small quantities of water under 2400 gallons.
Most water pumps are classified by the quantity of water they can pump in an hour.
This is referred to as gallons per hour or GPH. Submersible pumps are appropriate for aquaponics that are 1200 GPH or less.
The Pros of Submersible Pump
- They are pocket-friendly
- Their ease of set up makes them beginner-friendly
- They don’t produce a lot of noise
- It is cooled by the water, making the system self-sufficient
The Cons of Submersible Pump
- They cannot sustain large aquaponics due to their limited GPH
- Maintenance and repair of these pumps can be challenging, and the water erodes them over time
Inline Pumps
Inline pumps are located external to the fish tank.
They will pump more water than the submersible type, making them the optimal option for larger commercial aquaponics operations.
While the submersible and other pumps use GPH (gallons per hour) as their sizing unit, inline pumps are characterized by their horsepower (HP).
The inline pump installation sits between the fish tank and the grow bed, with one tube pulling the water from the tank, and the other pushing water from the pump to the grow bed.
The Pros of Inline Pumps
- An Inline pump is a very powerful motor device that can do large aquaponics wonderfully.
- This pump is air-cooled, and will never be subject to water corrosion.
- This pump can also be used to aerate the fish tank, and the grow bed to add oxygen to both, preventing fish death, and rotting fish.
- This pump will also last longer than most pumps.
The Cons of Inline Pumps
- It is costlier than the submersible type
- The motor system requires a lot of power to run and is noisy
How to Choose the Right Size Aquaponics Pump
It is important to choose the correct size of the pump to prevent stress to the fish and plants.
If you choose too large of a pump, then you will bombard fish and plants with nutrients and water, which will either kill them or put them into poor health.
If you choose too small a pump, you will pump insufficient water and nutrients for proper aquaponic production resulting in less productivity and/or nutrient deficiency.
There are three steps to choose an appropriate size pump for aquaponics.
They are:
- Calculating the GPH( gallons per hour)
- Estimating your aquaponics system’s head height
- Combining GPH and head height
Step 1 – Calculating the GPH
This action you perform will depend on if you are using a submersible water pump or an inline water pump.
Most pumps will have a GPH rating. However, some or many may have the Litre per hour (LPH) sizing.
A pump should be able to pump all the water in two hours.
Therefore, an appropriate aquaponics pump size will pump half of the total water amount once per hour.
For example, If you aquaponics system has a total of 1000 gallons of water, a suitable pump will pump at least 500 gallons per hour.
Therefore: The proper pump has a minimum of 500 GPH rating.
Step 2 – Estimating the Head Height
Head height is the distance from the water line in your fish tank to the top of the grow bed or tower.
For example, if you are using a submerged pump and the water level is 2 feet above the ground and you want to pump the water to the grow bed, which is 3 feet above the fish tank waterline, the head height is 5ft (2 feet + 3 feet) height.
The easiest way to estimate your head height is through measuring with a ruler or measuring tape to calculate the distance between the fish tank waterline and grow bed water level.
If the head height is longer for vertical grow beds and grow towers, you will need larger pumps which consume more power compared to smaller systems with short head heights.
If the grow beds are at the same height with the fish tank waterline, they are at zero head.
Step 3 – Combining GPH and Head Height
The ideal pump size for aquaponics lies at the intersection between the GPH and the head height.
Most aquaponics pump manufacturers will have a chart showing these two variables, so you can compare it to your system’s values as you determine the correct pump size.
Every pump manufacturer will have their own chart, so never use one brand’s chart to determine if one of their pumps is going to be suitable for your system based on another brand’s chart.
Reading and Interpreting the Curve on the Graph
Most manufacturing manuals will specify the GPH/head height graph with curved lines drawn and labeled.
To estimate the right pump for your aquaponic, go to the y axis, read the value that is similar, and draw a horizontal line that intersects across the curved lines.
Read the value on the x-axis and draw a vertical line.
The intersection of those lines will give you an estimate of the ideal aquaponics pump size.
Wrap Up
When planning to install an aquaponics system, the planning process must be exact, or you risk creating an undesired project.
If you are a hobbyist or are intending to make a larger-scale commercial aquaponic system, you will need to appropriately size your aquaponics pump.
For the hobbyist and small-scale farmer, a submersible pump works great as the pump will not exceed 1200 GPH.
An inline pumps are used for larger commercial systems as they have more power to pump large amounts of water.
Regardless of the type of pump, the factors to consider when the aquaponics pump must be properly sized are GPH (Gallon per Hour) and head height.
As the graph produced by the manufacturer indicates, the perfect pump will be the intersection of both the GPH value and the head height.