What Mom Never Told You About The GH Dual Diaphragm Air Pump

The GH Dual Diaphragm Air Pump

In this article, we'll guide you through everything you need to know about the GH Dual Diaphragm Air Pump. We're honest in our reviews so you can make a confident decision when buying your hydroponics equipment. This is a powerful, quiet pump and is well respected within the indoor gardening community. It's recommended for beginner to intermediate level growing and is suitable at providing oxygen to approximately four to eight, five gallon buckets of nutrient solution.

Name of Product

GH Dual Diaphragm Air Pump


  • Quiet, with rubber feet
  • Powerful
  • Two diaphragms to run multiple aquariums/airstones
  • Remains cool compared to other pumps people have used


  • Complaints that after one and a half months there was only 25% power from the pump but other people commented that it was probably the person’s airstones
  • Can have a leaky manifold



General Hydroponics



Model Number


Number of Outlets




Length (inches)




Width (inches)




Height (inches)



What’s the problem it’s trying to solve?

Plants need suitable oxygen levels in order to survive and the more they can absorb the faster they grow and the healthier live they can lead. If you don’t provide fresh water, the environment within the reservoir will quickly become deoxygenated. Thus, providing optimum oxygen concentrations is essential for taking your hydroponic projects to the next level.

Oxygen naturally dissolves into water but this is a slow process. Air pumps are the devices hydroponic growers use to considerably increase the concentration of dissolved oxygen into the reservoir. Pumps come with varying degrees of power output which affects the amount of air they provide to the nutrient solution. So, if you don’t have an air pump at the moment or you need one with more power, this has the potential to cater to your needs.

This animation explains how a Wilden dual diaphragm pump works, in case you aren’t well-versed on the subject.

Why did we choose the product we did?

The GH Dual Diaphragm Air Pump was chosen because of its impressive reputation amongst the hydroponic community. Reviews across the board are high, with the primary compliment being how quiet the pump is for how powerful it is.

We chose a heavy duty product capable of withstanding being outside in all weather conditions (as long as it’s sheltered from the rain) and you won’t need to worry about the quality of the product deteriorating. For instance, there are reports of users having had theirs outside for over a year with no complaints.

The GH Dual Diaphragm Air Pump draws 8 watts of power and has a maximum of 320 GPH/ 28,000 cc/min output. What does this mean? It’s relatively inexpensive even if you’re using it all day everyday and it’s pumping out a lot of air in the meantime. Most people recommend using this pump for four five gallon buckets. If you choose to use fewer buckets, you can shut off whichever of the valves you aren’t using.

The full story

Although most customers state the pump is one of the quietest on the market, there are some who claim the opposite and aren’t happy with the noise it makes. Perhaps they have a dud product, it happens, or perhaps they’re simply picky. It’s not a question we can answer. There’s information online stating the GH Dual Diaphragm Air Pump has been known to have air leaking from the manifold. This can result in noise pollution and result in air wastage which could’ve potentially be directed through to your airstones. Ultimately, it wastes money.

There’s a way to cure the leaking effect. Find yourself a thick enough glass jar to withstand the vibrations from the pump. This will prevent any noise escaping and annoying you. Plastic lids are better than metal lids as they’ll avoid rusting. All inputs to and outputs from the pump are going to come via the lid, through some drilled holes. Ensure you have a lid large enough to comfortably accommodate the holes.

The idea is to create a seal between the lid and the input/output so no air can pass. If you have the equipment, start by drilling tester holes smaller than you’ll need and work your way up until the cables fit through very snuggly. We’re not entirely sure why this is meant to work, presumably it raises the pressure inside the jar and forces the previously leaking air into the airstones.

This video demonstrates how to change the diaphragms on your pump with the General Hydroponics rebuild kit. It’s a simple procedure whereby you unscrew the pump’s casing and swap the old, worn diaphragms with the new ones. What’s great is the rebuild kit costs about a third the price of buying a new model altogether and saves you a lot of money in the long run.

In his video, Keyplayr61 has a faulty pump and you get to hear what it sounds like - loud and terrible. At the end, you can hear the finished rebuild and it sounds significantly better, good enough to have in a room in your home. His instructions are clear and methodical so if you need to go down this route you’ll be able to without any prior experience required.



If you’re undertaking any project with more complexity than The Kratky Method or the Wick System, you’ll need an air pump. Perhaps you’re looking to expand your existing projects and are in need of something more powerful to supply more nutrient solution adequately. Either way GH Dual Diaphragm Air Pump is almost guaranteed to meet your requirements.

All things considered, this is a really great piece of kit and we’re not alone in believing this. As stated, its power-to-noise ratio is excellent, perhaps the best there is. Moreover, it only consumes 8 watts of power, making it cheap to run for long periods of time.

We won’t lie to you and say it’s perfect (there’s no such thing), you may encounter some issues such as a hammering sound (the shaft needs to be centered) or a leaking manifold. But the disadvantages associated with the product don’t outweigh the positives for the average grower, hence the superb reviews.  

Would we recommend this product?

A lot of people are extremely happy with the GH Dual Diaphragm Air Pump, overall it’s a great product and we would happily recommend it. 

Open the comments form below and share your thoughts

Show comment form