Backyard Aquaponics
A place to discuss aquaponics

Indeed... I've posted on this subject many times... on most of the forums...

We have a phosphorus mind set obsession... nurtured by a century of phosphate driven soil fertilisation...

IMO... although Phosphorus is considered a "major" element... it's importance is greatly over-exaggerated...

Particularly as it has distinct inter-relationships between Calcium and Potassium.... (as you allude Yabbies)...

And can lead to lock out of either, or both.... most usually Potassium...

It's particularly relevant to Tomatoes that are both heavy Calcium & Potassium feeders... where excess phosphorus can not only impact on Potassium levels... but also on Calcium levels... and result as one of the causes of "blossom end rot"...

Yeh, sorry, I said "trace elements"... force of habit... but you know what I meant.

So what's our best plan of attack for countering a Phosphorus overload?

For a start.. don't use products like pH Down... that contain Phosphoric Acid...

Other than that.. as you said Yabbies... it's very rare to see an AP system with a Phosphorus deficiency... and frankly...

I think just as rare to see an AP system with Phosphorus overload.... unless the fish feed is some strange formulation... or an external input high in Phosphorus is introduced... like bat gauno, which someone was using...

By adopting the alternating Calcium/Potassium pH buffer technique.... IMO... you shouldn't really have to do anything much... or more than that...

And most systems seem to prove that everyday...

Most people on this forum will advocate the use of MAXICROP whic it's probably the highest source of phosporus introduced in any BYAP system. (and like Rupe mention inorganic industrial acids to adjust water parameter)
Second after that will be the fish food, then reduce feeds if you suspect there is a phosporus overload.

How do I use that technique?

I've got bad blossom end rot at the moment

In my case I was testing the nutrient water for phosphate content. It reached a maximum level of 5ppm before I transplanted the tomato plants into the system. Shortly there after I see no phosphate. Days go by and still no phosphate. Then the grow tips of the plants start to turn purple. I added 20lbs of Tilapia in addition to the 20lbs of catfish already in the system. Now phosphate ppm is slowly coming up. Right now around 1.5ppm. Plants are coming out of the purple growth.

I would like to test for K but have not as of yet found a way to do it other than the obvious by sending a water sample in along with $150 to get it done.

My plants show no other deficiency issues as of right now.

Just want to mention that I did try soft phosphate rock, which is readily available here in the US. This is a 0-3-0 soil amendment. It was applied directly to the plants. After application the plants immediately showed signs of improvement. This was short lived. Another application was done and again the plants showed improvement for a couple of days.

I do not suggest using this as a phosphorus supplement in an AP system for the following reasons.

1. Only 3% phosphate. The other 97% plugs up your system. Especially if you grow in buckets or grow beds. It didn't have an adverse affect on the grow rails.

2. Stains the water and everything else to a dark tan color.

3. Lots of heavy metals. All in ppm Arsenic 17.8; Cadmium 55.2; Lead 10.4; Nickel 95.7

Has anyone requested the heavy metal content of the Maxicrop product?

The advocation of periodic additions of Seasol, or Maxicrop... both relatively low nitrogen & phosphorus N:P:K products..... isn't restricted to this forum at all... it's almost universal in aquaponics...

And has always been "advocated" as a periodic supplmentation for trace elements... not for phosphorus...


The phosphorus provision into AP systems... from fish wastes... is a primary... ongoing, daily input.. unless you cease feeding...


I meant to address this in the other thread... and will do so later....

But I am not alone in suggestion of the use of inorganic compounds to address water/nutrient parameters....

It's always been commonly suggested and accepted practice.... in wastewater treatment, aquaculture.. and as the entire basis of hydroponics.... as well as more recently.. aquaponics...

And in general... in complete contradiction of your assertion as to those that "preach for chemotherapy"...

You'll find that in fact I have always argued against treating an aquaponics system as a laboratory system...

And only advocate the use of acid based pH reduction in specific situations... for specific reasons...by specific means and methods....

And the use of organic compounds... to buffer pH (up, or down)... or to provide trace element supplementation... is done with miniscule quantities... and only periodically....

By the way... the basic acidification in aquaponics... due to nirification... is due to hydroxyl and carboxyl acids.... organic acids...

In general, organic acids are weak acids and do not dissociate completely in water, whereas the strong mineral acids do... like hydrochloric acid...

And while acetic, and citric acids can be formed organically in plants etc... and are certainly known as "organic acids" becasue of that...

Applying a manufactured chemically made acetic, or citric acid... is no different.. than apply a manufactured inorganic acid.... within certain limitations/benefits...

I'm well aware of the use of Seaweed/kelp extract, my point was to highligh where a phosporus source could be coming from and how to lower it.
Have you ever wondered what is the ultimate difference between a balanced natural ecosystem and a man made overloaded system?
If your end means it's production of course you will just accept those methods that are industrially established and
proudly stand for those as the only way to control an overstocked man-made system!
Do you remember when everybody believed we live on a flat planet? Our mentality has changed a lot since then, I hope this will continue...
PS: By the way you have just mention the four industries that have greatly contribute to damage of the natural ecosystem, I would not use them as a valid example to be honest, the fact is now widely acccepted in aquaponics makes no difference, actually this exacerbate the situation.

By the way can some AP experts explain how the Aztec had a prosperous life just utilising pond mud on floating reeds barge and no use of any of that lab stuff that goes in the AP system to get a hanfull of toamtoes right.
What are we doing so different and what has it been changed ever since?
one word....industrialisation.

RupertofOZ

I find there are many companies that base their hydroponic solution on Hoagland. Definition here http://en.wikipedia.org/wiki/Hoagland_solution

Should aquaponic nutrient solutions be shooting for a close equivalent?

Fair enough....


The difference is simply that in a natural ecosystem... the balance ebbs & flows over time.. according to, and limited by natural inputs/outputs...

Manmade systems... are usually completely imbalanced... because we like to push the limits... beyond what a natural system might produce... and commercial food production is a good point as an example...

No arguement from me there at all...


And yes again... all the "industries" quoted.. have in the past contributed to some degree of damage to the natural ecosystem... but all of them have substanially cleaned up their acts over the last decade...

And both commercial hydroponics and RAS operations.... are now usually in most countries... based upon best practice.. zero effluent discharge from the property....

I'm not sure why you think aquaponics, backyard, or particularly "commercial".. would exacerbate the problem... unless by dodgey operators...

Especially with the vast majority of the water effectively being treated... and reused... one of the primary benefits (perceived or otherwise)... of aquaponics...


Indeed... they essentially worked with a natural ecosystem... and within the population bounds of the amount of feed that they could grow.... if they couldn't grow enough food for th population... nature would over time... reduce their population...

Given what you've written above.... especially as you seem to think that commercialisation of aquaponics will actually exacerbate environmental degradation... why are you choosing to go down this path??

Or how are you planning to address the problems you see... while still remaining a viable, profitable commercial operation...

Probably... in a commercial senario.... although it would take a few water tests... and data collection.. to see just what the nutrient composition of the system water was... and what might be lacking....

And that could, almost most certainly would (unless manipulated)... vary from season to season.. or by localised weather...

You'd probably need to gather 12 months of real time data to actually establish a baseline...


But as a general rule in a commercial sense.... why would you not want to control your nutrient profile... the same as they do in commercial hydroponics.. even if by other means... ie "organic" nutrient in puts...

The viability of a commercial operation depends on the quickest plant to sale time frame... and quality of the product...


P.S... just to be clear...

I am NOT advocating that anyone should make up a Haogland solution... and pour it into their aquaponics system...

IMO permaculture might not meet world food demand and as anything has it's limitation, yet I believe we can apply more of those concept to aquaponic (within limitation) and even further to the real commercial level.
I'm extremely passionate about the concept as well as the possibilities of application and I only try do follow common sense or seem to be a fair compromise between nature and mankind. (biological carrying capacity and regulating factor variables)
And like you said it's still very variable and subject to weather

I'm not a visionary or a missionary, the goal is to manage an aquaponic system in a more natural approach and still make it profitable (pay the bills in my case)

I'm creating a research platform where we are studying, monitoring and collecting data on those areas we think it could be managed naturally (any feedback or ideas are wellcome)

Once the first system it's established and running I will move on a PERMACULTURE PROTOTYPE system.

Some of our way to provide external source of nutriment, or itegrated farming is listed here;
companioning planting, comfrey juice, nettle juice, meal worm, white wood hash, BSF, worm brew, gammarus, Anodonta cygnea, lady bugs, bees, shellgrit, limestone, duck to keep slugs undercontrol, certified organic fish/duck feed, solar pannel, recycled vegies paper, recycled egg boxes, NO hydroton or alike, pig to compost the fish gut and bone, coconutfibre planter,willow planter, reeds bed, jute fiber, bamboo NFT, no PVC, cork DWC raft.....etc...

I've read many good info on this forum for which I'll always be tankfull to the whole community and the creator, hopefully with more input coming I will achieve this envision.


"THE ONLY WAY TO AVOID CRITICISM IS TO SAY
NOTHING, DO NOTHING, BE NOTHING."

Better to grow the cherry tomatoes if you aren't a greenthumb as they are much more resistant to all the common disease. The key to good tomatoes is lots of calcium in the form of gypsum.