Prodigious Organic Diffusion RAS

© K J Gordon



POD RAS: What is it?

It's an organic approach to RAS without the stress.

What is the most efficient filtration system on the planet?
Answer = Gravity over distance applied to water flow.

And gravity is free. The POD RAS aquafarming design uses this principal to a huge advantage. (the less pumping the greater the profit)

The answer is not complicated and expensive machinery and super high tech digestion units. Yes they all work to various degrees however, cost and maintenance often out weight any commercial advantage.

Ergo, the enormous amount of failed and derelict RAS farms in Australia. The original POD RAS farm is still in operation thirty years later. This, is exactly where RAS has to go. Sustainable, organic, profitable farming.

Incidentally, I have managed the most complicated RAS, and the largest RAS, in Australia so I know how complicated they are to run. 150 separated RAS enclosures each producing several tonne per year. An absolute nightmare to manage commercially!

The simple way is the profitable way to RAS aquafarming. In many ways you really don't need the rubbish high tech approach unless you don't care about a profit margin.

The POD RAS design is modular and can be scaled to meet proposed outcomes. It can operate up to 60-70kg per cubic meter as a final density.

It is this density that gives the greater growth rate and also the most efficient FCR. I can design you a farm for the future and walk you through construction and culture.

A POD System is very power efficient at 3.5kwatts per 18 hours per 20 tonne production total.

A POD RAS farm uses waste aquatic plants or hydroponics “built in”, for a large percentage of nutrient digestion. This then becomes valuable compost.
Aquafarmer can supply the design or build the entire module either in plastic tank of earthen pond. Personally, I prefer in ground ponds.

Call or email for a free discussion today.




Turn Key POD RAS Construction Concepts

Design Concept for a 2000 Tonne POD RAS

'Simplicity of Application'



"Recirculating Aquaculture Systems are like V8 SUPERCARS. You need special skills to drive them, they cannot be driven on normal roads and a bad crash will kill indiscriminately".

So Why Not Build POD Recirculating Aquaculture Systems?

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I find it interesting that RAS has such a following. Personally, the intense nature of RAS is not my idea of relaxing aquafarming.

Round the clock monitoring

Back up power issues

High Electricity Consumption

Full time Staff required at a rate of 1.7 per 4 tonne of production. Not Good!

(Dutch Aquaculture has 4 staff per 1000 tonnes of fish production)

Short working life of RAS Components

Return on investment 5 to 14 percent.

Or Loss of Investment

High Mortality (Fish)

Stress (Human)

Gray Hair (Human)

Divorce (Human)

You get the picture

Kel Gordon's Aquafarming Summary

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However if one approaches the design concept correctly the outcomes are both financially and aesthetically rewarding as you can see below..


Prodigious Organic Diffusion RAS




The POD RAS Design Uses Only One Pump!

The picture above is a two module RAS system we designed and built in 1986. This farm was, private catchment, private disposal. The aquafarm was vertically integrated with hatchery, nursery and growout production. It was and still is capable of 30 tonnes production per module every 18 months.

And that equates to $726,000 AUD per 18 months on today's prices.


Small AquaFarm Production Cost Summary

(Kel likes to earn $100,000 per year)

Wages = $150,000

Feed = $200,000 standard pellet diet

Electricity = 10kwatts x 18 hours@40cents/kwh = $72/day x 500 days = $36,000

(Kel also likes a new 4WD, strictly for work you understand)

Vehicle = $80,000

Set Up Costs @20% /crop = $100,000 (owned the land and borrowed $300,000 at 14% = $42000 pa interest)

This farm has a hatchery but if the farm needed to buy fingerlings

100,000 Fingerling @ $0.75 = $75,000

Sundries at 10% = $64,000


ATO Profit = $21,000

(Primary Producers should study the above figures closely as this business is designed to be a one person operation)

Do you see any mistakes?

YES! There is no live feed production program..

This design is about life style just as much as it is about profitable aquafarming. Call for a one on one with Kel Gordon today.

+61 458 427 520

Yes, if you run animals you do have losses. The above format is a little tongue, and done so on purpose to basically say fish farming should be a pleasure and not the high stress primary production failure the RAS industry has become. Pay close attention to the potential for profit.

A POD RAS uses more water volume in its passive filtration than 'normal' RAS designs. And this usage is where running costs and wages are dramatically saved.

The POD's final culture density is ten tonne per megalitre of water. However first year of culture it is highly recommended that this figure be maintained at five tonne per megalitre.The culture process is designed that way as not every aquafarmer has degrees in applied water chemistry and will make mistakes. Every person in RAS does make mistakes.

The POD RAS does not run on the sharp edge of culture density for exactly this reason. And, who really wants to grow fish like battery hens? Good product is only grown in stress free environments.

And to me personally, RAS should be about a comfortable and rewarding life style. I believe that is what the POD RAS represents.

A POD system requires one staff person full time and three persons for harvest. That is 1.2 persons per 66 tonnes production per 18 months. The whole farm operates on 1000 liter per minute flow rate per individual RAS system, and there are two modules in the top half of the picture.

Each RAS utilise's a multi-stage mechanical and biological filtration system that is, maintenance free.

The farm above utilised in ground ponds and plumbing with an expected working life of 25 years

The water leaving the biofiltration was drinkable.

Return on production costs was 67%.......

This farm produced the best looking and healthiest silver perch I, to this day, have ever seen. And that includes wild stock.

"Not too bad for the eighties".

If you are building an RAS system then the above components are basic and essential for low stress, long production life RAS Aquaculture.

Here is an interesting design. Fish are only cultured in the lower right hand system. The rest of these covered tanks culture zooplankton and whiting. What is not shown is the hatchery/broodstock management. Which is the backbone of new aquafarming

The above Kel Gordon POD System is the first generation of NEW AQUAFARMING (sustaining the world)


RAS System Design : Our commercial experience with RAS design and operation is well known in Australian Aquaculture. From pond recirculation designs in the 1980's to fault finding and commercialising Cumminscorp Ltd C-Box efficiency in 2006.

Warning C-Box systems were fundamentally flawed.

If you are thinking seriously about RAS Aquafarming then aquafarmer's free advice is to stop now.

Unless you have a significant understanding of RAS aquafarming this process is completely unsustainable and unprofitable.

If you must proceed,,, build a legitimate pilot scale operation and run it for at least two seasons. We can provide on-going input into development projects.


There are so many Recirculating Aquaculture Systems around today it amazes me there is such a lack of success. Then again maybe it doesn't. There are well defined books, miles of research and yet it cannot be said that there is one successful RAS in Australia. I think that first POD design near Taree NSW was 30 years ahead of its time.

And yes there are many claims in RAS Aquaculture but for any aquaculture business, success can only be measured in profits over time. Can anyone tell me of an aquaculture business that has been profitable for the last 10 years?? Well, except for the one mentioned above.


Contact Kel Gordon to discuss your plans





Aquafarmer builds RAS systems for profitable longevity and really, that is the only necessary factor an RAS system should and need for sales promotions.

For any questions on RAS operations Contact Us



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