The Complete Guide To Sizing Hydroponic Pumps

The Complete Guide To Sizing Hydroponic Pumps 1

To size your hydroponic pump, you need to consider several factors such as the type of system you’re using, the water volume, the desired flow rate, and how high the water needs to move. It’s important to understand that there’s no one-size-fits-all approach, as each system has unique requirements as well.

But before you size the pump for your hydroponic system, you need to decide whether you need an air pump or a water pump.

Do you need a Water Pump or an Air Pump?

There are several popular hydroponic systems used by growers worldwide. Each system utilizes a different method of delivering nutrients to plants, which influences the oxygen needs of the root systems that the way nutrients are delivered to the plants.

In deep water culture (DWC) systems, plant roots are suspended in a nutrient-rich solution. These systems rely heavily on dissolved oxygen for growth.

As such, DWC systems require a robust air pump to provide a consistent supply of oxygen, ensuring plants receive enough for optimal growth and health.

Other hydroponic systems like NFT, vertical grow towers, and Ebb and Flow systems require water pumps. For instance, NFT utilizes a shallow, continuous flow of nutrient-rich water to nourish plants. These systems require water pumps that provide a consistent flow rate around the clock.

Ebb and Flow systems, on the other hand, involve flooding and draining the grow bed with nutrient solution, so the pump size will depend on the water flow rate and bed size.

Important Hydroponic Pump Ratings

There are various ratings for hydroponic pumps that you need to understand when selecting a hydroponic air pump:

I. Flow Rate

Measured in gallons per hour (GPH) or liters per minute (LPM), this rating indicates the volume of water a pump can move in an hour. It’s essential to choose a pump with a suitable GPH rating to meet your system’s oxygen and nutrient delivery requirements.

II. Pressure

The pressure a pump can generate is usually measured in pounds per square inch (psi) or Pascals. While not as crucial as GPH for most hydroponic systems, it can be helpful for specific applications, such as aeroponics.

III. Horsepower (HP)

This rating signifies the pumping power of a pump. The higher the horsepower, the more powerful the pump, making it suitable for larger systems or those with more demanding water flow requirements.

IV. Maximum Head Height

The maximum head height refers to the height of the highest point the water needs to reach within the system. This factor is crucial for any hydroponics system with vertical components, such as vertical grow towers. You’ll need a pump that can efficiently move water to the necessary height without losing significant power.

Hydroponic Air Pump Sizing

The job of hydroponic air pumps is to provide oxygen to the water in your nutrient reservoir. As such, its sizing is relatively straightforward and can be done using a handy rule. Use one of the following rule-of-thumbs to size your hydroponic air pumps.

The first rule relates the required flow rate of the air pump to the volume of water in the system.

Select a hydroponic air pump that can supply 0.5-1 liters per minute of air for every gallon of water in the system.

This translates to 16 GPH of air for every gallon of water. For most hobbyist indoor gardeners, even the cheapest pumps can deliver this, although you need to think about your pump in operation.

The second rule selects the wattage of the air pump based on the volume of water.

Select a hydroponic air pump with a rated wattage equal to the number of gallons of water in the system.

To distribute the air evenly throughout the system and enhance oxygenation, use air stones or diffusers. The size and number of air stones required will depend on your system’s size and the air pump’s capacity.

More air stones will result in higher pressure drops. So, ensure that your air pump has enough power to supply air to all the air stones.

Hydroponic Water Pump Sizing

Sizing a water pump for a hydroponic system requires several steps starting from the calculation of the volume of water needed to the calculation of how many gallons of water are needed, the required pressure, and the selection of a pump model.

  1. Calculate the total volume of water in the system, including the reservoir, and the grow bed.

volume [gallons] = (length [feet] × width [feet] × height [feet]) × number of containers × 7.48.

  1. Determine the desired flow rate of the system. You can do this by dividing the water volume by how often the water needs to be completely replaced.

Flow Rate [GPM] = volume of water [gallons]/time for completely replacing water [hr]

  1. Next, measure the head height of the pump. This can be done by physically measuring the height of the highest point water needs to reach from your optimal water level in the reservoir.

Most pumps for hydroponic systems end up losing between 15-30% of their pressure head. So, multiply the head by a factor of 1.3.

  1. Check the performance chart of the pump, which shows how many gallons per hour it can deliver at different heights or depths.

Performance charts are provided by pump manufacturers and normally have data for multiple pumps in a single chart. From this, choose a pump that can deliver the required GPH at the desired head height.

Remember, that you might not find an exact match. In this case, select a pump that can supply more than the required GPH at the selected pressure head.

The Complete Guide To Sizing Hydroponic Pumps 2

Compare the power consumption of different pumps that meet the performance criteria. The power consumption is usually given in watts (W) on the product description or manual of the pump.

Choose a pump that has a lower power consumption for higher efficiency and lower electricity costs. You can save more on energy costs by running your pumps on solar energy.

Selecting the Types of Water Pump

Besides sizing the water pump for your hydroponic system, you also need to select a type of water pump. The right choice depends on the water requirement of your system.

The two main types of water pumps used for hydroponic systems are:

  1. Submersible pumps, as the name suggests, are submerged in the nutrient solution within the reservoir. These pumps are compact, versatile, and more energy-efficient than inline pumps. Submersible pumps are well-suited for small to medium-sized hydroponic systems, with a water requirement of 1000 GPH or less.
  1. Inline pumps are installed externally, typically placed outside the nutrient reservoir. Inline pumps are known for their powerful performance, making them ideal for larger hydroponic systems or applications that require higher head and flow rates (more than 1000 GPH ).

Special Considerations for Different Hydroponic Systems

Each hydroponic system type has its own mechanism to deliver the nutrient solution to the plant roots. Therefore, getting the right-sized pump for each one has some special considerations

A. Ebb and Flow Systems

When sizing a pump for an ebb and flow system, first determine the length of your flood intervals and measure the height of your optimal water level.

Additionally, you’ll need to know the water volume you need to pump and how high it will need to be pumped above the water line in the reservoir. Flood and drain systems also require knowledge of the water volume and height to pump above the reservoir.

B. Nutrient Film Technique (NFT) Systems

For NFT systems, a constant flow of water 24/7 is necessary, with a shallow water depth. When choosing a pump for an NFT system, you’ll want to select one that can provide a consistent and even flow of water, ensuring all plants receive the nutrients they need.

C. Deep Water Culture (DWC) Systems

DWC systems do not require a water pump. Instead, they need an air pump to oxygenate the water and promote root growth. When sizing the air pump for a DWC system, ensure that it can provide sufficient aeration to maintain oxygen levels and support healthy plant growth.

D. Vertical Grow Towers

For vertical grow towers, pump sizing will depend on the specific design and requirements of your system. Consider factors such as water volume, head height, and any unique design elements that may affect the pump’s performance.

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Maintaining Your Hydroponic Pump

Proper maintenance of your hydroponic pump is crucial for ensuring its efficiency and longevity. A clean and well-maintained pump will not only work more effectively but also produce less noise, providing a more enjoyable indoor gardening experience.

A. Importance of Proper Pump Maintenance

  1. Enhanced efficiency: A clean air pump operates at peak efficiency, ensuring optimal dissolved oxygen levels in your nutrient solution.
  2. Reduced noise: Regular maintenance can help prevent excessive hydroponic air pump noise, which can be disruptive to both you and your plants.
  3. Extended lifespan: Taking care of your pump will prolong its life, saving you money on replacements and repairs.

B. Cleaning and Maintaining Your Hydroponic Pump

  1. Inspect regularly: Check your pump and its components for signs of wear or damage at least once a month.
  2. Clean filters and airstones: Remove and clean filters and airstones regularly to prevent clogging and maintain optimal airflow.
  3. Lubricate moving parts: Apply lubricant to any moving parts, such as bearings, as needed to reduce friction and wear.
  4. Check tubing and connections: Examine airline tubing for kinks, cracks, or leaks and replace them as necessary. Ensure all connections are secure to prevent leaks or disconnections.
  5. Monitor noise levels: If you notice an increase in hydroponic air pump noise, it may be a sign that the pump needs cleaning or maintenance.

C. Tips for Extending the Pump Life

  1. Follow manufacturer guidelines: Adhere to the manufacturer’s recommended maintenance schedule and instructions for optimal pump performance.
  2. Operate the pump within its capacity: Avoid overloading the pump by using it within its rated capacity and specifications.
  3. Keep the pump clean and dry: In the case of air pumps and inline water pumps, ensure that the pump and surrounding area are free from dust, moisture, and debris to prevent damage and maintain efficiency.

About The Author

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Gina Harper grew up dreaming about farms and growing her own food. She began an urban garden to feed herself and turned it into an incredible hobby. Gina is here to teach you everything from raised beds to container gardening, how to keep plants alive and well in a smoggy city, and the works. It’s time that we carve our own piece of green earth and reap what we sow—she’s here to help you with that.