Backyard Aquaponics
A place to discuss aquaponics

I hope no one on this forum is here to attack new ideas, but what Gary is doing (1000 litre system) is being done very successfully elsewhere. Australia is a leader in aquaponics and has many excellent experts. Over in the Americas, Dr. Rakocy and Dr. Savidov are the best known aquaponics experts. They both have years of success with many styles of systems. What I wanted to point out is Dr. Savidov is in Crop Diversification in Alberta, Canada. He has a dozen or more systems on roll around carts. They are highly successful and allow concurrent testing of many combinations of fish and crops saving years of research time. Dr. Savidov is a very practical APPLIED researcher. I have photos of his cart systems from my visit with him last summer. The plants are fantastic with massive healthy roots and the fish I saw were Tilapia and they were in excellent health. He also has a large system with four 100' x 4' beds and six 4m dia fish tanks, sediment tanks biofilters, etc. Both do exactly what they were designed for and each has its own management requirements.

Gary is doing a proven approach. All the merits of that style of system he pointed out quite well. He also recognizes the need for frequent observation in a small system. I think all that is true.

My wife likes to travel; I like to homestead. Both need to be accomodated. I also need to attend conferences and do contract work that take me away. Anyway, a large, computerized system that can be accessed, monitored and controlled over the internet is my goal. My stocking density will be so low, I will get about 300 pounds of fish a year from 3000 gallons ( 1lb fish per 10 gallons). I have lots of redundancy, dual pumps, battery backup, error detection, low power strategies for power outage, etc. If I am away and the system has a fault, I have time to see the problem (e-mail alerts) and call a friend to help (likely another engineer tha can handle most anything).

Many types of system can be effective for many differing approaches. In Garys place, I would do it his way.

DB, I don't think anyone is attacking new ideas, for as you said, it's not a new idea.

Personally I have 4 systems that have fish tanks of 1000L or less, and I'm in the process of designing and building another one at the moment with a fish tank of 1000L. From what I have read in this thread, most people are reitterating a very valid concern that GD mentioned as well.



There are many people on the forum that aren't very experienced with aquaponics and they need to understand when reading through a thread like this, that it's not necessarily easy.
Also I feel that when someone makes bold statements like below, then it's fair enough that others may not take them as gospel



Hey GD, do you have your shed insulated? This would be a very efficient way of helping to keep the heat in. Wilson Lennard had everybit of his shed insulated and this kept the water temperatures fairly constant. And were you planning on having your growbeds/satelites etc outside of the shed? will there be any recirculation or will most of the plant water be to waste? I'm just trying to get more of a picture of things, especially about the water flows.

Doug_Basberg, I like the sound of your system - quite the opposite to GD's system in approach too...
And I would not attack GD's system - just concerned as I am aware of what COULD go wrong (I guess its a side effect of being a teacher for so long) But I am VERY interested to see the progress of this system and will not say 'I told you so' if things do go wring. In fact, it will be a real pity if they do go wrong as GD has put a lot of effort into this project
I look forward to congratulating GD on this system as he shows us these fish he is spending a great deal of effort on - I prefer success to failure

Say, could you post some of those pics you were referring to, just fore interest's sake - I would love to see them (if you have the time that is)

Hi EB,



Nothing of what I've read about on this site is a new idea. In fact, I've never seen anything begin to approach the innovative integrated food production systems of the New Alchemists......and they were put together 25 years ago.

I accept that many people like the easy, safe way.....I like to push the boundaries.

I feed duckweed and Soldier Fly larvae when it would be much easier to feed fish pellets. I use coco-peat when most other people are using gravel.....or something else. I happily use non-recirculating systems when the conventional wisdom says that recirculating is the way to go......and, when someone says that 3 - 4kg per 100 litres of water is the upper limit, I wonder why it can't be 6kg.....or 8kg.....or 10kg per 100 litres.

I know that the fish pellets, gravel beds and recirculating systems work (some very well) but I'm inspired by the thought that there might be something out there that works even better.



My shed is not insulated but I agree that would help to maintain constant temperatures. Covering the tank would be the easiest thing to do but, as it stands, the temperature in my tank hasn't dropped below 23 degrees C .......night or day......in weeks.

My tank is inside the shed and my grow beds are outside of the shed.

The water from my fish tank runs through my two 65 litre bio-filters continuously with the excess flow squirting back into the tank.

My small gravel grow bed (one square metre) is flood and drain and runs off a little aquarium pump and a timer. During the day, it operates for 15 minutes on the flood cycle and is allowed 30 minutes to drain. I adjust the drain with a small 19mm valve.

The rest of the growing systems.....comprising about 15 trays, 10 satellite pots and two 50 litre tubs.....is run-to-waste coco peat. It's getting hand watered (with a short hose and a wand) every two days or so (it's been quite hot in Brisbane for weeks now). Every few days, I'll add about 80 litres of aged mains water or rainwater as a top up.



People don't have to accept what I say as gospel. When I refer to being able to put a system capable of produced an average of 1kg of fish per week in a system for under $500, I intend it as as statement of purpose......a goal. I'll get around to describing the system as soon as I find the time.

Of course, if someone wants to lay down the gauntlet and issue a challenge, I'll probably do it even sooner.

As for the claim about small tanks that........"I can grow fish....and vegetables......faster. In fact, I can grow the same amount of fish in a small tank as someone else can in a larger tank just because I can achieve greater control of the parameters".....I believe I have explained why that's the case already.

If things (fish and plants) grow faster in the optimum conditions (and they do).....and I replicate those conditions (and I can)....then it necessarily follows that I can produce more fish per litre of water than someone who is not able to control the growing parameters to the same extent.

It's a matter of simple logic.

I concede the risks associated with intensive small tank operations and I drew attention to them as part of putting what I believe is a balanced argument....and I've also made it clear that this is not the sort of operation for someone who is not prepared to exercise the appropriate standard of management.

I can also cost effectively bulletproof small systems using backup pumps, water flow alarms and sensible testing and feeding regimes.

Gary

Gary the passion and ideals that drive you are evident to anyone that has looked through not only this thread but your website...

You are prepared to live and breathe your beliefs and convictions in a way that others may not be either able to or prepared to do, perhaps because they don't share the same fire that you do or perhaps only because of location, circumstance or other personal constraints.

At times this may mean that it appears to you, or that you may appear to others to be at odds to more "mainstream" ideas or opinions.

In the end in doesn't really matter either way, you will derive your happiness by following your own "path" and I applaud you, in some ways envy you for doing so.

I appreciate your motivations and the goals you have set with regard to AP... i.e a modular system for $500... I wish you all the luck, for I'm someone who through sheer monetary and positional constraints (renting) have a similar and vested interest in either developing something within the same parameters or by benefiting from what you acheive...

I have reservations as to whether it's possible to acheive your goal, but..

(1) I'm sure you passion will drive a result as close as possible to that end

(2) That others can and will only benefit from what you attempt/acheive.

You have most eloquently/clearly outlined your goals, constraints, parameters and desired outcomes...

There can be no criticism of anything you propose and I really don't think that anyone here really intends or implies any....

Go gettem I say... even if you can't prove them wrong or acheive all your goals... you're going to come a lot closer than anybody else who doesn't push the boundaries

New ideas are very, very rare. Most people never have one, a few lucky people have a few, einstein had 20.

I have been reluctant to post some of my thoughts for fear of being accused of being mean spirited - which is not the case at all. Having met you in person and had lengthy discussions about our respective systems and plans, I'm sure you will realise this Gary.

I would just like to further explore some of the ideas that have been posted here, for benefit of all. I think some respectful debate is always beneficial.

Gary - I think I have a pretty good grasp of your system from having read about it here, seen pictures and seen it in person. My biggest concern with your system is that the bulk of the growing volume/area is made up of the coco-peat planters and trays that are hand watered and run to waste.

My concerns are not that they are hand watered (though I personally would prefer not to have to hand water and love the automated flood and drain concept) or that they are run to waste (because I expect that the absorbent nature of the coco-peat and the method of watering means that there is little or no waste - in fact less evaporation that if using a gravel bed). My concern relates purely to the fact that this part of the growing system would remove only a small % of the nitrate being produced by the fish in the system.

Correct me if I am wrong, but approx 80 of 600 litres (13%) of the systems water is removed every 2 days and replenished with clean water - resulting in a removal through this part of the system of 6-7% of the nitrate concentration accumulated over a day.

In addition to this - you have a 1 metre square gravel bed that water cycles through in a 15/30 minute flood/drain cycle. I expect that the reality is that it is this part of the system that is keeping things on track for you - yet so much concentration is given to the pots - which are essentially just that and not strictly part of the part of the aquaponics system at all. I have no problem with watering pots or conventional gardens with nutrient rich water from the fish tanks - in fact I intend to do exactly the same thing myself with my large system (watering my conventional gardens with fish water instead of tank water and replacing the fish water with tank water - same amount of water used but so many more benefits for garden and system). I think NJH hit the nail on the head a couple of days ago when making a comment in the Satellite Pots thread. He said ‘if the requirement is that the pots are simply watered with fish water, then my whole garden is a satellite system ’. On this logic – my 80 square metre veggie garden (very sad at moment under water restrictions) will soon be a satellite system – which is fair enough.

If you were to increase the stocking rate in your tank to the levels that you propose to operate at - I believe that this would require more flood and drain or continuous flow beds, unless you intend to remove and replace a larger % of your water each day - which could become a bit labour intensive (and not holiday friendly for those who want to holiday). Also – for those without rainwater collection – it would also require a lot of neutraliser use.

I know you have spoken in the past about the nitrate flashing off due to high oxygenation of the tank. I'd like to know more about this - because if it is correct I expect that my nitrate levels would be regulated by this method. I have a heap of oxygenation though the flood drain action in my bed, the powerful waterfall caused by the sipon (running about 50% of the time) and the great venturi in the fish tank (thanks Muzz) - running 100% of the time. To date I have not seen any real indication of this in my system - though I truly hope this will happen because it will reduce the volume of beds I need to stock the fish at the rate I would like.

In summary:

- none of this is meant as criticism, but I hope prompts some open debate
- I personally have found that the biggest challenge – particularly when stocking a reasonable amount of fish, is nitrate removal and I am not sure that a satellite system watered by hand is a solution to this in lieu of a decent amount of F&D or CF beds using whatever medium is chosen. Of course nitrate removal is the whole crux of AP and what makes it different to a recirculating aquaculture set up. Ammonia and nitrite conversion is a piece of piss once the system is cycled – provided there is a decent amount of bio-filtration.

Thanks Gary

I run my irrigation system using a pressure pump that takes water from the fish, the fish water is topped up using a floating-ball-valve from our rainwater tanks. I've not had a problem with clogging....yet. I'm only using brown drip line stuff, which seems very clog resistant - apparently if it does clog you can just put mains water through it with the tap open at the end and it will unclog most of the time.

I put some calcs on nitrate removal here: http://njhurst.com/~njh/blog/20061220
When I wrote it, I thought the idea was a no show, but since then aeldric has convinced me that it is perfectly reasonable. It comes back to the fact that given a suitably high NO3 concentration the plant will take up all the NO3 and all the water at roughly the same rates (transpiration etc).

NJH - I just read that part of your blog and I think I understand it. Unless I am missing the point - it simply confirms to me that with a high stocking rate (feeding 4.5gms per day to 4,500litres is far from that) then I would not be removing the nitrate sufficiently unless I was using a large % of the water in the open loop system and replacing it with fresh water.

Am I missing the point

Just thinking njh....

I would expect that in a high nutrient system like AP that the lifetime for lettuce would be probably half the 70 days you have based your calculations on... confirmation from others please

And it is possible to pick and replace throughout the cycle...

How would your figures work out at around a 30-35 day lifespan??

BTW NJH - I could never quite work out how David was going to stock a decent amount of fish and remove his nitrates either. He was kind enough to provide me with a copy of the write-up the paper did on his system and I also read with interest what he posted here. Does he have many fish?

should be, especially if you grow from seed - just stagger you sowing of seed... that way you have seedlings comming in when you remove mature plants...

and ....



Well maybe in away VB we all are....

What Gary is doing is not dis-similar to what the guys at...

Barramundi Blue
Taylor Made
EcoCity

are doing.... albeit on a much larger scale...

only they are using lots of hydro trays and x% "run to waste" BUT IT WORKS....

Why??....

Because the common factor in all their systems AS IN Garys...

and Dr. Savidov and Travis???

THEY ALL RUN SEPERATE BIOFILTERS...... and run to waste

Begs the question then.... just what percentage of the potential "nitrates" are being stripped by the bio-filters??....

I ask that bearing in mind previous discussions as to the effect of nutrient strength over distance/plant uptake etc...

Perhaps though this needs to be looked at more closely in terms certainly of what percentage of "nitrate" or "potential" nitrate measure is made up by the solids component... that which is removed by the bio-filter....

Isn't this exactly what occurs in a normal "aquarium" filter system???

Rupert, you are referring to mechanical filtration rather than biofiltration for solids removal. Biofilters just house bacteria really. Mechanical filters catch sediments. In aquariums, these functions are often combined in the same unit, and may also include chemical filtration. Hence the confusion, I'm sure.

Removing solids mechanically would remove some 'potential nitrate'. I wonder if we can get some of our budding scientists here to do an analysis of 'poo' content?!? Or maybe for some ballpark numbers we look at established figures for earthworm castings or bat guano, for example. Running to waste (aka 'water changes' in aquariums) and adding plants will also remove both nitrate and 'potential nitrate', of course.

Hi VB,



I sincerely regret any impression that anyone might have that I am intolerant of their attempts to counter or challenge my ideas. In my mind, that's what debate (and learning) is all about. If someone has viewed my passionate defense of particular viewpoints as intimidatory I apologise.

As you've observed VB, you've met me and you've seen what I do and you understand what motivates me.

That this debate is of interest to other people, is evidenced by the number of people who are following it. One of the nice technical features of this forum is that you can see who did what and who went with a particular post on any given date. This is important, because not everyone is moved to comment but it's useful to know that they are still engaged somehow.

To return to the debate at hand......

VB, if I understand it correctly, your concern is that of nitrate removal.

Well, the answer is disarmingly simple.

In all of my nitrate tests, so far .....and I've almost emptied the nitrate test bottles in my test kit since I bought them in August last year.....I have never seen a nitrate reading in my system above 20.

For months, I thought that there was something wrong with my system because it just didn't seem to produce enough nitrates.....particularly since, in the early stages, I had very few (and very ordinary) plants.

One of Steve's comments from around that time suggested that because my pH was low, my system was 'resting' and the other possibility was that the amount of air in my system was causing the nitrates to 'flash' off as a gas.

As my fish grew, and feeding rates increased, I added more plants and they are clearly using any nitrates that are available based on their rate of growth.

You are correct when you forecast that, as the fish approach maximum weight, rising nitrate levels will require more flood and drain beds.....or more run-to-waste growing systems.....and I look forward to providing them and I accept that I'll use more water doing it.....as you would with any other growing system.

You see, I want more than fish and salads. My goal is food self-sufficiency so I have to produce fodder for my chickens and quail and other small livestock.

I don't think that the parallel between my coco peat systems and regular soil-based gardens is strictly correct. My coco growing systems offer most of the benefits of flood and drain gravel beds (and some others that relate to the size of the containers)....the only difference being that the water doesn't return to the tank.

I'm not too fussed about the hand watering......I can automate that anytime I choose.

Gary