Thanks again for the many replies and especially the data I was looking for! Well yes, that looks
very different indeed!
TCLynx wrote:
As to measuring the nitrate levels in a grow bed compared to the level in the water, I'm not sure how you can really do that.
I guess that it would be possible if one really wanted and if it was relevant enough. Actually one just needs to extract a sample from the inside and analyze it (quickly before break down releases more). Afterwards I agree that it isn't that important realizing the more dominant fact that nitrogen is actually released constantly, little by little.
TCLynx wrote:
Though I would not really Say that aquaponics is more like soil gardening, here is an analogy I might make.
Right, I didn't express myself properly here - what I meant was that
concerning nitrogen content and release, a AP growing bed should rather be compared to soil (gardening) than to hydroponics. And only because of the fact that the permanent release vs. actual content (as in a nutrient solution) is probably something that some 'hydroponists' without insight may often misunderstand, respectively underestimate. Although, the actual nitrogen content in both, growing bed as well as fish tank is higher as I expected.
TCLynx wrote:
A mature AP system is to a mature organic soil garden as Hydroponics is to a chemical soil garden.
Sorry, the problem with comparisons is always that they lack something and are never fully accurate (which is the very nature of any comparison)- you can always compare things to illustrate something, but from my understanding it's often smarter to leave it there. Btw. what the hell is a "chemical soil garden"? I never heard this term in my live...
Let me reply in a different way without quoting, just giving a personal statement on some of the topics you brought up, followed by some
general explanations I'd like to put in here:
I think that nobody is immune to misconceptions and that most people have a general tendency to use preferences and idealization instead of being as objective as possible. This often leads to a more or less distorted view and sometimes simply to wrong ideas. (it goes without saying that I am no exception here).
Another problem comes with names and designations. Formerly, (etymologically speaking) a name or designation was chosen in order to describe a thing in a best possible way. Today it seems more like if names and designations were created to misguide and mislead in the first place. Sometimes the better sounding designations and terms win with one length over the most descriptive.
Let's start with Aquaponics, - where is the fish?! Why isn't it called Pisciponics (pisci = latin fish)? Because Pisci may remind something embarrassing and could sound rude? Aquaponics sounds better, - and here we go: it's essential that it sounds good - who cares if it's most descriptive or characteristic! While the term "organic" was the first choice and became a commonly accepted designation. "Naturally grown", another term (in fact sometimes used for some aquaponically grown products, that wouldn't get the "certified organic" label for some reason), is in fact more descriptive and accurate but only used for "non-certified organic" products. Why is that? Anyway, for a non-native speaker of english language (as myself) organic sounds a way odd. I remember, that in the 70s when I studied art (sculpture) we used the term ORGANIC to describe sculptures that where inspired by asymmetrical, non-geometric but rather round shaped or voluptuous (feminine) shapes - kinda psychedelic stuff. What else would a vegetable be at the end than organic? Have you ever heard of inorganic vegetables?! Perhaps there is, but those are used for decoration purposes only. The actual irony is, that there is any plant on the whole planet that is able to absorb any organic matter. As we learn sooner or later, organic matter needs to get break down to a molecular level that can be absorbed by plant osmosis. And here we get to the next term "chemicals": and this-one is a real jawbreaker! All of us consume (actually need) a certain amount of NaCl on a daily basis, - but actually most call it table salt. There are different kinds, qualities but you can reduce them all to NaCl. No-one tends to call it a chemical though. But what is it,- is it a natural product or is it a chemical? Well it probably is what you want it to be! Wait a minute - not exactly, because in fact it is a chemical component that was processed by nature (in most cases). And here we got an important difference, - that needs to be pointed out to really understand what is what in this context, regardless how it is called.
A few more examples: there is a German based company that produces a very popular fertilizer type that is sold around the world. And well they "legally" call the chemical components they use (I am not sure about all countries and the respective legislation) "nutritional salts". So it happened (years ago), that I had a hell of a debate with a german guy who was supposed to be the "fertilizer Guru" of a certain forum. He simply claimed that there couldn't be anything wrong with this product, as they only use "nutritional salts" to manufacture that product. And here he simply was kinda "brain washed" by the so nicely sounding designation "nutritional salts". In fact those are nothing else than exactly the same ingredients that are also commonly used in virtually all fertilizer types for any purposes (including nutrient solutions for hydroponics). But the brainwashing with names and designations goes in both directions. Some antagonists tend to use the term synthetic fertilizers, but most of the compounds in use are not synthetical, not per definition and neither from a pragmatical perspective. Some people use pot ash, to complement potassium in AP, others prefer potash, and even others call for potassium carbonate, or even K
2CO
3. Is it always the same chemical compound, no matter how you name it? Call it coincidence or deadly irony, the only chemical that one actually should call synthetic(al) is in fact Iron Chelate (EDTA) which is sometimes used with AP as well, to complement Fe.
In Hydro, people use to call the
very same stuff "nutrients" and most of them completely ignore what they are actually using at the end! But that's actually the general state of the art. Why? Probably because most people actually don't want to know what's actually going on under-knees. But not only people who are actually using fertilizers based on chemical compounds seem to not want to know exactly what they're using to grow their food with, - people who in fact refuse to use those, seem to not know what they are actually turning down and do repudiate. Could it be, that both simply guess that they know enough, to either accept- or refuse the use of it?!
There is another very common fallacy, mostly used by people who turn down "chemical fertilizers". They simply equate industrially manufactured fertilizers and pesticides. If I am not mistaken, I've even understood the claim that the use of chemical fertilizers directly implies the use of chemical pesticides - which is simply a misconnection. Have I or haven't I heard from someone, that this applies to hydroponics as well? In case this is a common belief, I'd bluntly say that its as absurd as the former claim. I can't see any direct connection here. Also, while most greenhouse hydroponics are kept kinda sterile and bacterial activity is not required, needed respectively not even wanted, it is not a general role. Actually so called "organic nutrients" for hydroponics REQUIRE bacterial activity and a setup with enough adequate media to allow bacteria to decompose these "organic nutrients". Even with standard nutrients you aren't obliged to keep the whole enchilada sterile. For instance, I am using organic media, together with basalt and river gravel - and there is bacterial activity in my buckets - you bet! I am even introducing beneficial fungus, like trichoderma harzianum in my setup, to prevent other fungi to settle. This can even be done directly through the nutrient solution, but if I would sterilize the thing, I'd kill the trichoderma harzianum culture as well.
But back to those chemicals and fertilizers! Is there actually something wrong with them - and if, what is it what could clearly and objectively bring us to the conclusion that it's conclusively and clearly inappropriate, wrong, a bad or even evil thing,- to use them!?
Well, the good news is that what we call chemical fertilizers, aren't composed of any poisonous, strange, mainly synthetic or other fancy components, ingredients or substances. Why? Because there has never been any intention or interest to do harm or poison any plants or the consumers of those! And also, why producing any fertilizer in the first place, that contains something abnormal, fancy or whatever that plants can't actually absorb or don't ever need!?
Are these chemicals pure and not contaminated with any fancy things? Even classified as fertilizer grade, single components are amazingly pure (up to 99%) (I could also say "some" here - as it's actually hard to tell or to compare) . Even less contaminated with heavy metals or any other poisonous or undesirable substances as many soils unfortunately are already. Here in Thailand for instance, 15 plant species have been officially declared "forbidden for composting", because these species tend to accumulate atmospherical and other soil contamination (that does not provide from any fertilizer)! Why are these chemical compounds cleaner compared to some soils? Simply because most of them are extracted from uncontaminated minerals from underground mining. Some of them are byproducts as a result of the manufacturing process of other compounds (also issue of minerals or other inorganic raw materials). The cheapest (like calcium nitrate and magnesium sulphate) obviously undergo less complex processes and/or are extracted from abundantly available sources. While more expensive compounds (as mono- or diammonium phosphate), are extracted through more complex processes and/or extracted from more expensive or rare raw materials.
And here I instantly switch to the bad news (before you all get upset with what I am telling you here): all of these components are obviously manufactured industrially; and as we know, this process stresses and abuses the environment and mother nature. Here it gets nasty, as a matter of facts. And the very next really down turn point is (in fact commonly known) the terrible abuse that actually goes on since the introduction of chemical fertilizers. When I said that they are industrially manufactured, it goes along with the treatment of acids, heating (which uses a lot of energy), and most certainly with some chemical waste, that we don't know of (which would be possible to determinate for each single compound, though - if ever one wants to know about all the details). In addendum, one must cite the abuse of nitrogen that is probably the worst part of it. This abuse is probably linked to the low production cost of nitrogen compounds. This is most likely the reason as well, why most fertilizer manufacturers tend to over do it with the Nitrogen content of their products.
Someone said earlier that their must be a reason why hydroponically grown veggies get no "organic" or "organically grown" certification. No offense at no time here, but while this statement is purely speculative your honor, I can tell the most obvious difference. The difference with hydoponically grown is that the actual elements needed for plant grow and development (in fact all the "stuff" that is absorbed by osmosis and used to grow plants and finally the product we talking about) isn't issue from organic decomposition, but is provided in already decomposed and ready to absorb form. But oddly enough all elements that are actually absorbed by any plant's root osmosis (in either case) are the same! The devil resides here in the detail or the way it's broken down.
I once had another debate with an expert in chemistry and plant nutrition. And I once "accidentally" claimed, that on the molecular level their is no difference between what is used in a classical hydroponical nutrient solution, and what is eventually dissolved after break down in any soil's water. One must add here that plants are not only unable to absorb any organic matter, the molecules must be found in ionized form, dissolved in water before osmosis can take place. Means that whoever may think what difference there is, - after complete breakdown and ionization to this level, there actually isn't any. However, what I claimed during that debate was NOT 100% justly formulated, and the expert (I was having the debate with) couldn't resist to corrected me eventually. When I said earlier that in nutrient solutions iron is delivered by EDTA chelated iron, this is actually a different molecular form. Because here, the chelates have bind already with the iron molecules, - while in soil, plants produce their own chelates, which bind only eventually with the iron molecules to then enable plants to absorb Fe. The chelates produced by the plants unfortunately go to "waste" somehow, if Fe is administrated through chelated iron. Because there are any free iron molecules in a nutrient solution they can bind to - one could even say that these chelates become some sort of contaminants. One more exception in a nutrient solution is apparently the dissolved potassium phosphate (in case there is any - some nutrients don't come with this compound). While it is dissolved in a nutrient solution, it is said to release some phosphoric acid. If that would happen during breakdown of Sulfur or Potassium, in soil and near a plant's root zone, it would most probably damage the roots. While in a nutrient solution it's diluted in water as quickly as it is released - and hence can't do any harm. Btw: phosphoric acid is ingested in form of soft drinks by millions of liters on a daily basis by half of the planet (even though there is a controversy about it's health risk). Anyway: we afterwards settled (well more or less) that my claim was basically true but couldn't be used as a generalization - as there were those specific exceptions I have been missing firstly and narrating about now.
I wouldn't abuse of any "argument of conversion" here, but nevertheless I have always been against what is commonly called chemical fertilizers. But from a retrospective perspective, only because I completely ignored what they actually are and how similar they are to what plants anyway need and absorb in soil's water. I've been strictly against the use of CHEMICAL fertilizers (it was even part of my education), also for hydroponics, - because I imagined that if so many "good" people, including "my brothers in arms" and others who basically think like I do, all say that its just the biggest crap there is, it obviously must be avoided like the plague. Even though without knowing exactly what it is and what it does! It's crap, that is reason enough to not even have it around your home!
I still don't like the way the stuff is produced and the enormous abuse there is, - but what should I say about the computer I am using as I type, - what about those plastic reservoirs, hydro or aqua...tanks, runs, tubes and cables, valves and pumps, - you name it it's f***ng synthetic and industrially manufactured. On top of it, most probably by some third world exploiter in disrespect of the environment and nature. If it wasn't I couldn't even afford it.
There is misconception and there are controversial ideologies and the inevitable discussions on every level. In fact there are so many about any imaginable topic around, that one must make choices about which topics to simply let go and on which to engage...
Backyard Aquaponics
Damn I's and O's 
