An Open Letter to AquaponicsHQ
Gary, I would appreciate if you would publish the following letter in response to a recent post on your forum by member Crusty.
While the poster was courteous enough not to actually name myself, or the client, sufficient information was posted as to make it obvious to which it was directed.
Unfortunately, while I agree with Crusty’s general sentiments expressed within the post, the attempt to justify his premise by reference to myself and the installation is unfounded and without knowledge of the facts.
The post stated…
Quote:
Recently a fish kill by an aquaponic kit installer and the associated "sorry to hear that" and "we feel for you" responses had me thinking about what we think is acceptable care for animals we are responsible for. This large system was built for a customer and stocked with plate size trout and now the heat has set in a few months later, they are dieing a slow and painful death.
Are we not able to find out where certain species will only grow with the assistance of environmental controls such as heaters and chillers?
Is information on fish species temperature tolerances not freely accessible on the internet or a phone call to an aquaculture association
For the benefit of all members of your forum and yourself Paul;
An extensive twenty page report was prepared for the client, before commencement of the project, which contained compilation of historical mean and maximum temperatures for the suggested site based on averages for over twenty years of Met office data.
The report also listed species data with regard to temperature tolerance ranges of numerous species that were suggested both as the client’s preference and those which in my opinion were best suited to the suggested site.
The site in question has a wide range of seasonal temperatures ranging from possible snowfalls in winter through to possible high temperatures for short periods in January.
The site is also historically consistently breezy all year round, especially during the night, and consistently partially clouded during the day.
The mean minimum temperatures for the site are as follows;
• January – 14 degrees C
• February - 12 degrees C
• March – 11 degrees C
• April - 8 degrees C
• May – 5 degrees C
• June – 3 degrees C
• July – 2 degrees C
• August - 2 degrees C
• September – 5 degrees C
• October – 6 degrees C
• November – 8 degrees C
• December – 12 degrees C
The mean maximum temperatures for the site are as follows;
• January – 25 degrees C
• February - 24 degrees C
• March – 22 degrees C
• April - 19 degrees C
• May – 15 degrees C
• June – 12 degrees C
• July – 11 degrees C
• August - 13 degrees C
• September – 16 degrees C
• October – 20 degrees C
• November – 22 degrees C
• December – 24 degrees C
Variance over twenty years of Met data was +_ 1 degree
The client had always indicated a preference for Barramundi and Trout. I was quite adamant that without substantial heating, Barramundi were not a viable option. I expressed a belief that Trout were a possibly viable all year round option, with the caveat that it might require the incorporation of a chiller for periods during January, and possibly February.
Winter temperatures necessitated that the aquaponic grow beds needed to be housed in a greenhouse with an appropriately thermal rated greenhouse film, and various options were presented to the client in this regard.
The necessity of housing the grow beds in such a rated greenhouse highlighted potential problems with controlling fish tank temperatures if the fish tank was also enclosed within the greenhouse and a deliberate decision was made to house the fish tank in a separate shed to allow for the ability to either heat or chill the fish tank according to species requirement.
The separation of the components, and unknown thermal transfers from heat transfer through the grow beds housed in the greenhouse, and any ambient transfer within the fish shed, posed thermal modeling questions that were beyond my expertise or any real time data available at the time, and this was clearly indicated to the client.
As such a respected firm that specialized in such matters was engaged to do some thermal modeling in order to determine the necessary capacity for a chiller if it was required.
The system configuration has proven difficult for even the firm commissioned to determine precise modeling and the reality was that actual real time data needed to be plotted over the first months of summer.
The decision to stock the system with 50 plate sized Trout (in 3000L) arose almost by accident, when due to a marital breakdown, an existing RAS operation about 30km away,
(running Trout all year round in a shed with no chillers) offered whatever stock I could remove within a few days… (as an aside, while I rescued about 400, about 2500 trout were dumped).
The size of the trout meant that the client could begin eating them immediately (much to their delight), and at a stocking density of 15kg/1000m3, with approximately 3000L/h of supplementary aeration I considered the management of the system to be within acceptable boundaries.
It was always accepted by the client, that if temperature limits were approached before the stock were culled down, and/or an appropriate chiller installed, they would be removed and smoked.
Shortly after stocking the client advised they were departing on an extended overseas trip, and myself and the farm manager were asked to maintain the system.
The client indicated that they would consider the purchase and installation of any chiller, based on the then recently commissioned modeling, after their return, and that if required any stock could be dealt with as required if the need arose.
For the record, of the 50 trout stocked;
• 13 were eaten by the client prior to their departure
• 2 died due to problems with solar battery backup system failure
• 10 were smoked/eaten by myself
• 10 were smoked/eaten by the farm manager
• 15 died due to extreme temperatures before action could resolve the issue
• The system has never had ANY water quality problems other than a single instance of over-feeding by unsupervised visitors. No fish were lost and water quality was returned to normal overnight.
The circumstances leading to the (openly) reported deaths were un-seasonally extreme;
• A week of day temperatures above the mean maximum by 5-10 degrees
• A week of night temperatures above the mean minimum by 5-10 degrees
• A week of zero wind chill factor, both day & night
• Increased greenhouse temperatures due to the failure of one of the fans
• Time constraints of both myself and the farm manager during the period
• Late delivery, and under-specification of an evaluation chiller
• Non-delivery of a pump component for the chiller, and subsequent delay
The client was advised at all times of events & actions, leading up to, as they unfolded, and eventual outcomes, and is entirely satisfied.
While I stand by my advice, and actions taken with regard to this project, I’m happy to both report it openly and honestly to all concerned. And to learn from it, and indeed accept any constructive criticism or assistance from anyone that might like to input.
Similarly, I agree with Paul with regard to his general concerns regarding the health and welfare of fish in aquaponic systems.
And as such I have, as have others, consistently opposed stocking densities of anywhere near the levels that both yourself Gary and until recently your associate, consistently stated.
Indeed I suffered the resulting ban from this forum because of it.
I have also consistently argued the need to frame stocking ratios within the perspective of the requirement for sufficient filtration and oxygenation for feed rates, as opposed to ratios based on fish tank volumes
And make such recommendations regarding stocking rates and supplementary aeration accordingly to all my client installations and/or anyone who seeks my advice regarding their own built systems.
For the record, of all the kit systems I have installed, the number of fish kills in my client systems has been insignificant.
In terms of my own losses… and your snide assertion that;
Quote:
Australian aquaponics' emerging title-holder in the fish killing stakes (who went off to college to learn how to keep fish properly) has a growing number of fishkils that amount to negligence, water quality issues and poor equipment design.”
I have always been prepared to report both my successes and failures, and reasons for it. Sadly, you have been reticent in doing likewise, other than those noted in your recent post.
For the record;
• I lost Silver Perch due to a power failure and a tripped power board
• Of the 20000+ trout fingerlings I’ve transported over the last couple of years, I’ve lost about 500. The bulk of those when I stupidly forgot to turn on/check the oxygen supply to the transport tank
• I have successfully transported and supplied over 10000 Silver Perch, Murray Cod, Tandanus, with virtually zero losses
• I have successfully arranged importation and distribution of 2000+ Barramundi from SA
• I lost about 60 trout when they literally jumped from the tank overnight, for reasons that I still cannot explain
• I lost about 30+ Barramundi last Anzac Day when the air temperature plummeted 10-15 degrees in a matter of hours, and the fish tank about 10 degrees overnight
• I recently lost about 200kg of mature trout while I was away for reasons documented
• I have been eating trout at least twice per week for the last two years, and currently still have over 40+ vacuum packed in the fridge
• I have successfully grown out and eaten over 100kg of Silver Perch and still have about 60kg
• I currently have about 30kg of Barramundi rapidly approaching plate size or larger
If you want to count the failure to check that I had turned on the air supply to the transport tank as “negligence”, then I’m guilty.
And I’ll put my hand up to water quality issues as a contributing factor in the Barramundi trial, although over-stocking for the available filtration was more the significant factor.
Poor equipment design??, well I would have done a few things differently if the time and money had been available when I initially set up my systems, and most certainly would have utilized top notch system components likewise if I had been able to afford them.
Like most people, high range purpose built aquaculture tanks and accessories were beyond my budget, and most of my income has/is spent in actually attempting to build a business and service my clients, who I do supply with what I consider to be quality, well designed equipment within the price rang of the existing market.
As to
Quote:
“I agree.....but those who irritate me most are those who spend plenty of time arguing against adequate filtration and then regale us with tales of fishkills and disease.”
If this is directed towards myself, then again it is a distortion of fact. While I might not advocate the complete removal of solids from an aquaponics system, as you have recently come to do, despite your protestations to the contrary, I have happily recommended and employed the use of (albeit small) external filters as supplementary filtration in both my own systems and advised visitors and prospective clients accordingly.
Likewise, as I’ve stated before, I have long argued against the trend of doubling stock densities while halving the (then) accepted filtration capacities.
And have always noted the requirement for solids removal and/or pre-filtration with regard to NFT and raft style operations.
Where we may differ is within the traditional “flood & drain” model, but I’ve always couched densities and ratios within filtration capacities.
I don’t know what you seek to achieve with reference to “who went off to college to learn how to keep fish properly” … and it’s of no real consequence, but for the record, while other commitments prevented me from fulfilling my studies over the last year, my record in previous years of study has seen results of high credits and distinctions. With 8 of my assignments achieving 100% marks. For reference, they related to water quality, stock health, and fish disease.
I do not count myself as an aquaculture “guru”, and indeed Crusty may have greater knowledge than I do, and I’ll happily learn from it.
Nor do I count myself as an aquaponics “guru”, although I might claim as much experience as most, and more than others that do.
And while Paul’s recent systems demonstrate extensive aquaculture knowledge and a good understanding of aquaponic principles, I doubt that he at this stage would claim demonstrable success or “guru” status
But then, while your knowledge of both fields, particularly aquaculture principles, certainly seems to have risen sharply since Paul’s arrival on the HQ forum, and you have reasonable competently compiled a book concerning aquaponics, in my opinion, and others, you haven’t really documented or demonstrated any personal aquaponics successes to warrant “guru” status either Gary.
I’m still confused as to why the need for personal attacks and jibes seems to continue, other than perhaps for either some kind of commercial competitive advantage or pure ego.
Positive criticism is one thing, and welcomed, especially if it helps advance aquaponics. But to make snide references, or attribute references to events without knowledge of the facts, generally or specifically, is just un-productive.
Backyard Aquaponics
