General Hydroponics HGC728040 Dual Diaphragm Air Pump 320 GPH 4 Outlet

Last Updated On Monday July 6th, 2020
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General Hydroponics

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- The best price we've seen on Amazon in the past 12 months was on April 16, 2020. The current price is considered high. It is 18% higher than the cost at its lowest.

currently high price

Up 4%

Updated July 6, 2020
Last Sale

Apr 26

for 18 days

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Current price is higher than the price on May 14, 2020.
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Price Activity

DatePrice ActionChange %Price Level
6 Jul, 2020Price Increase3.75%high
14 May, 2020Price Increase11.30%average
26 Apr, 2020Price Drop-10.15%low
22 Apr, 2020Price Increase16.86%average
16 Apr, 2020Price Drop-14.43%lowest
Update on 6 Jul, 2020 price change % swings above and below average price

Showing: Area under 0 show price is cheaper than average. Above 0 shows higher price than average.

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We also found 1 products that redditors have recommended that are the best alternative to this product or are related accessories.

Recommended in microgrowery

General Hydroponics	HGC728040	Dual Diaphragm	Air Pump 320 GPH	4 Outlet

Product Details

  • Sold on
  • B008UF9XLY Amazon ASIN
  • General Hydroponics Brand
  • GH2716 Model Number
  • General Hydroponics Manufacturer
  • Categories

    Diaphragm Pumps, Pumps, Industrial & Scientific, Hydraulics, Pneumatics & Plumbing

Reddit Reviews and Recommendations

  • 8 Reviews
  • Jan. 20, 2020 Last Review Date
  • April 30, 2015 First Seen Review Date
  • 3 Reviewed on Subreddits

    hydro (5)
    microgrowery (2)
    aquaponics (1)

Discussion and Reviews on Reddit

A few weeks difference. [R]

5 months, 2 weeks agojohnsbury posted submission on microgrowery.
Jan. 20, 2020

DWC Basil Troubles [R]

3 years, 1 month agolyagusha posted submission on hydro.
May 21, 2017


My first grow! And I've been trying to my best to raise a Thai Lemon Basil and a Sweet Genovese basil for close to a month now. I've researched a ton and educated myself to the best of my abilities but when it comes to diagnosing sick plants...I've got nothing. Any help would be much appreciated, very in depth details and thoughts below.

Raw Details

  • DWC using 2 cylindrical air stones run by two ports off of an Ecoair 4 (full setting), other two ports are closed
  • 2 Sweet Lemon Basil, 2 Sweet Genovese Basil
  • 200 Watt Full Spectrum 6500K LED Fixture
  • 3" Net Pots
  • Water and nutrients...Currently have 6 gallons of distilled water in the bin with 5 teaspoon of GH Floragro and 1 teaspoon of GH FloraMicro, PLUS 1 teaspoon of CALiMAGic...General Hydroponics is meant to be one teaspoon per gallon depending on what stage your plants are in...I go a slight bit under as I've heard that's better?
  • I keep as close to 70F as I can
  • Roots look fairly good and white, perhaps a little brown but I honestly think that's due to the deep brownish red color of the CALiMAGic, they were pure white a half week ago before I started using the CALiMAGic.
  • Water is kept as close to 6 pH as possible with a pH meter and is currently sitting at 200ppm -Roots do not feel slimy


Think the plants drooping is largely due to the high temps in the tent when they were young. Last week or so I've had ambient air issues figured out so general heat isn't an issue. The leaves are definitely burnt in some areas but with a rough hand test I really cant feel a huge heat difference between ambient and under the light. I keep the light about 10" above the plants. If I had to diagnose this I'd say its all burning and heat issues but I really think I have that largely figured out and the plant isn't rebounding at all, just looking worse and worse. Some may also notice the odd bubbles on the leaves of the thai lemon basil, more heat issues? On to nutrients.

Should I genuinely be using 6 teaspoons of Gro and 6 teaspoons of Micro in my distilled water with say 1 teaspoon of CALiMAGic? My tap water is actually fairly solid, if I run it though the Brita once it comes out as 200ppm. Should I just use that instead of distilled? I'm also getting some Hydroguard soon to help with root health. Speaking of root health I still don't feel like the EcoAir4 is putting out a ton of bubbles in the tub, does anybody have experience with moving from an ecoair to a more commercial model of air pusher?

Any help is much appreciated!

3 years, 1 month agolyagusha posted on hydro.
May 22, 2017

Diaphragm air pump. Bought two and never looked back. Very quiet and dependable, I've had one running continuously outside for a year with no noticeable reduction in air flow.

Critique my setup before I buy it! [R]

3 years, 5 months agoshaxsy posted submission on hydro.
Feb. 3, 2017

Looking to get into window-sill DWC hydroponics for herbs / veggies this spring. Here is the setup I am looking at, tell me if it is feasible!

Containers: Use 4 of these, side by side on my window sill

I will plan to paint them matte white to block out light.

In each lid, I will put 3x 3-inch net-pots with clay pebbles. I am starting most things in an aerogarden but will transfer them over once they are of size and there is enough sunlight this spring to provide natural light.

Aeroators: Hoping to use this for aeroating all 4 containers, splitting each out hose, and connecting an air stone.

This is what I'm curious about the most. Will this provide enough aeration, splitting each out into 2, therefore only needing 1 pump for all 4 containers.

I know different plants need different nutrients, and I will manage them each seperately. I haven't gotten that far quite yet! Of the 12 plants I hope to grow, they will include:

1 container of peppers (banana and 2 jalapeno) 1 container of tomatoes, maybe a strawberry plant 2 containers of various herbs.

3 years, 5 months agoshaxsy posted on hydro.
Feb. 4, 2017

One stone per container is fine. I would buy a better pump like this one and use that to power all the pumps. I have about 5 of these and they work great.

When is aeration helpful for circulating water? [R]

3 years, 6 months agoDec. 22, 2016


3 years, 6 months agoIdflipthatforadollar posted on hydro.
Dec. 22, 2016

Unless its a commercial air pump, which you dont need for 10 gallons it should be whisper quiet. Look into the Eco whisper series, they come in various sizes, all of which are quiet until you get to the commercial level. IF you feel you need heavier air output from a commercial size BUT you also need it quiet id go with

Its what I use indoors for DWC 60 gallons across 4 reservoirs and it does fine.

TLDR; Your pump can be small enough that you shouldnt even hardly hear it running if at all

Noob Question Re: Setup [R]

4 years, 3 months agojustmeinflorida posted submission on hydro.
March 22, 2016

Im looking into building a DWC setup in my basement and have been doing a bit of research before I jump in and buy the equipment. One thing I haven't been able to figure out is that its often recommended to buy a Rubbermaid or similar bucket and then drill holes into the lid to insert net pots.

What im not clear on is if you were to fit 8 net pots into a bucket, would you have to grow all the same plants in those 8 net pots? Or should I be trying to find plants that require the same PH/PPM/Lighting and grow those together?

Im looking to start out with lettuces and herbs which I was going to have in two separate containers. but looking at some of what is required it seems like some herbs wont grow together so I would need multiple buckets.

Which adds a separate complication of do I now need to buy multiple airpumps to manage the separate buckets?

Any advice is appreciated!

4 years, 3 months agojustmeinflorida posted on hydro.
March 22, 2016

Here's the pump we bought for multiple buckets You can even tee them off to do 8 buckets.

Air pumps for large systems [R]

4 years, 4 months agogoltoof posted submission on aquaponics.
March 7, 2016

Overestimating my volume a bit but this is overall what I'm looking at:

Total gallons - 4500-7000 gal

Sump - +4000 gal, surface 160 sqf

Beds - +1500 gal, 20'x3'x8" (x6)DWC beds

Pump housing 50'-100' away from beds.

All tubes must run underground, outdoor application.

Must be quiet, energy efficient, durable.

What kind of pump(s) tubing, fittings, stones would you buy in my shoes? Could/should all of this be run on one pump? Each pump will have a backup on standby, of course.

4 years, 4 months agogoltoof posted on aquaponics.
March 7, 2016

> Korean diaphragm airpumps Like This?. Have you used this pump? How many do you think I need for my system? Looks like regen blowers pull way too much current.

Update #2: My Beginner DWC Hydro Setup and Follow Along [R]

4 years, 6 months agolyagusha posted submission on hydro.
Dec. 27, 2015

Hey everyone!

Once again, thanks for following along with my attempts at growing many different kinds of vegetable/fruit plants indoors with hydroponic methods.

So just a quick recap: First PostSecond Post

I planted the seeds on 12/11 and it's now 12/27. During that time, I've gotten my Masterblend nutrients (which I have yet to use) and my lights 4 tube t5 high output florescent.

Here's what the plants look like now! Getting their first true leaves:

So I'd love to hear what everyone thinks about the plants quality and health, if they're looking like they need any more light or nutrients. It's probably too early to tell but I did notice that giving the plants their night and day cycle promotes growth a lot!

I have 4'' net cups with hydroton and my DWC ready to go, I would like to thank people like /u/DevIceMan for great advice on treating the plants when they are young. When should they be moved into the DWC? Should it still be awhile?

Thanks again for any advice or tips but just for reading! Hopefully more people will get into it.

Yes, I know my handwriting sucks, I wrote it with my right, I'm a lefty. :)

4 years, 6 months agolyagusha posted on hydro.
Jan. 7, 2016

Basil, as with all plants, enjoy lots of air. The more air the merrier. The container they are in looks like 14-18 gallon, for which I would recommend an 18 watt ecoplus pump, or even better this diaphragm pump, which though expensive, puts out amazing amounts of air and does not overheat. My watermelons loved it.

How much air for DWC [R]

5 years, 2 months agoCharLsDaly posted submission on microgrowery.
April 30, 2015

So I have been trying a (NOT recirculating)DWC grow for the first time. It's by far the most robust grow I have ever done and by far my favorite method of growing I have tried.

An issue I am having is I was wondering how much air you folks know/think should be pushing per bucket(I use 3.5 gallon bucket/2.5 gallons water). I've heard a watt-gallon ratio, but I dont think thats right because I have seen some lower wattage pumps push more than a similar watt pump. So do you guys know how many LPM's/LPH GPM/GPH, Im sure I can do the conversion? My current pump kills it(60 LPM for 9 buckets) on air, but is so loud that you can hear it through the floor downstairs and has an awful humming noise. I just blew $120 on a acoustic foam mat below the buckets(this is where the noise is coming from not the pump itself. I've scoured the internet for info and don't have any real good results as to optimum LPM/LPH or GPM/GPH of airflow, so hopefully some of you can help.

5 years, 2 months agoCharLsDaly posted on microgrowery.
April 30, 2015