Backyard Aquaponics
A place to discuss aquaponics

what instrument can be used to measure the nutrient levels in AP water ...ie iron , calcium, zinc, pot, etc etc ?

A mass spectrometer might be able to measure that kind of wide variety of things, not sure it is in the budget of the average home gardener though.

You can get test kits to test for things like Iron, calcium and many other elements but to test for everything you would probably be spending thousands of dollars on test kits. For backyard growing the freshwater master test kit plus maybe a few others is usually all people need.

For Small farm to commercial growing one might want to invest in some extra testing. I have kits for the normal stuff plus Iron, calcium, phosphorus, chloride and a few others. I based what tests I needed to track more regularly on some professional lab testing of some water samples and also what tests were recommended to me. (some tests will be more effective/easier to use than others so it sometimes doesn't make sense to test for something if the test doesn't work very well and you can identify a problem based on observation of the plants and other things.)

thanks TC ... just trying to take the guess work out of what is in the water , i agree looking at plants is a key , i prefer to know the problem exactly and deal with it ... i use the master test kit as well , can i ask what individual test kits you use for the other elements you mentioned ? i did come across a company in the states called La Motte they have individual test kits ( titration i think) and also a portable bench photometer which is electronic ..cheers

Yes most of my other test kits are LaMotte.
Keep in mind that this is aquaponics and you really need to resist treating it too much like a chemistry set or hydroponics. As in make sure you have a well established bio-filter before you start worrying too much about all the other things.

Take note that the photometer is just a test READER. You still have to run the tests using the appropriate re-agents (either tablets or drops or whatever) and then the photometer looks at the color and compares it for you instead of you having to trust your own eyes to read the test compared to the card or other optical comparison.

Getting the test kits doesn't necessarily take the guess work out of it, it only perhaps makes it easier for you to make more educated guesses. Lets face it, we don't necessarily have a baseline for aquaponics that tells us exactly how much of each given nutrient we need in the water for each different kind of plant and most of us are not growing just one single type of plant anyway. In hydroponics they have that info but since we are not using hydroponic mineral salts in a sterile environment those guidelines are not necessarily appropriate for aquaponics.

To work up that kind of guidelines for aquaponics to take all the guesswork out of it, would probably require years of work by some one with many medium to large size systems with a lab and full staff to test/sample water and plant tissues and well as some fish health experts to figure out what the optimum levels of everything would be. And those guidelines would likely only be really accurate for their growing environment along with the particular type of fish, fish feed and source water that they have.

Sorry TCL... but I totally disagree...

The nutrient requirements for most plants are (as you say) known... why would plants in aquaponics have any less, or more, need for a required nutrient profile... than those grown in soil, and/or hydroponics...

Isn't aquaponics a combination of aquaculture and hydroponics

Aquaponics is not some sort of miraculous transformation of the principles of plant growth... or nutrient requirement...

Aquaponics is merely a methodology for plant growth...

If what you say was true... then there would be NO basis to suggest that "commercial" aquaponics could be possible... or successful... before establishing such baseline data...

Rupe, according to most "Hydroponic" baselines, many of the Aquaponics systems out there that people are having great success growing veggies in "totally don't work".

I've had people insist that the Nitrate level HAS to be over 200 in order to grow veggies but we know that it is often possible to grow a great crops in systems that sometimes read practically no nitrates because they are so well balanced.

It is kinda like the people who insist that the EC has to be at some arbitrary number because that is what the hydroponic book told them.

I'm not claiming that ALL hydroponic guidelines or targets are completely useless for Aquaponics but more that they are not necessarily going to remove 100% of the guesswork out of figuring out how to balance an aquaponic system.

Are you not one of the primary people who tells people to quit playing with their aquaponics systems as if they are chemistry sets?

If one bases what their aquaponics system tests should read like on hydroponics, you may wind up seeing people dumping huge amounts of phosphoric acid and potassium hydroxide into a system while they are trying to get their potassium and phosphorus readings up to what the hydroponics nutrients would do while they are also perhaps seeing massive pH swings and bounces in the process.

Now suggesting that "commercial" aquaponics is no possible without such baselines....... Well I know very successful farms that are not necessarily using all the high tech testing and fertilizers but they are growing very successfully organically. And I expect that most small farms that have a successful aquaponics element to their operation or operating more "organically" and I'm not talking certified organic I'm talking they set up a small aquaponics system just to test it out on their farm and started experimenting to see what worked well and then expanded or built additional systems to capitalize on what was effective in their location, with their water, feed, supplements, etc to grow something of value to their market/farm operation. This did not necessarily require them to test every element in their water and add things to make it match what the hydroponic book said was "optimum".

Now if one is trying to set up say....... Specifically an aquaponic pepper farm on a large commercial (say 6 acres or more) scale to produce a certain amount of peppers per week every week starting at a given point. Well then, they probably better make sure they can fine tune their operation to growing specifically the peppers they are probably already contracted to sell and that would likely take into account basing much of their operation on getting the nutrient, pH, temperature, humidity, etc etc all as close to what the books say is optimum for growing that kind of pepper (or whatever it is.)

I am doing some lab testing on my water as well as having test kits to test from more than just the master test kit here at home and I do look at "hydroponic baseline recommendations" but my farm/systems are growing a bit more "organically" so I'm not taking those recommendations and hard fast rules unless the plants are telling me they AGREE while the fish/bacteria don't object to the additions. I'm using those hydroponic recommendations as a reference point, not as removal of all guesswork. For instance, we know that EC won't measure the same in Aquaponics as hydroponics most of the time since aquaponics doesn't use salts in the same way.

thanks for the input guys , you mention baseline hydro growing levels can you expand on that ? what i am aiming at is if you want to grow a specific fruit or veg in your small comm system , surely you must prepare the nutrient levels to be correct for the chosen variety .... so Rupe how do u test ?

I just feed the fish and the plants grow...

CDM, I don't test my system water... beyond reading basic values of pH, ammonia, nitrite, nitrate, DO and temperature.... some more often than others, most only occasionally

Some people in backyard aquaponics, and perhaps a few in "commercial aquaponics".... may get an initial water test analysis to identify any potential problems... i.e well, or bore water... levels of carbonate hardness/metals...

But very few people would regularly test their water in aquaponics... even those running so called "commercial aquaponic" systems... (most wouldn't know what to do with the results anyway... )

The nutritional needs for optimised fish species growth and plant species growth... are all essentially known from decades of research... and specific nutrient deficiencies can be corrected if determined...

Aquaculture, hydroponics and agricropping all basically take the approach of providing a surplus of nutrients... for one reason or another...to ensure optimal growth...

And as such there are always excess nutrient wastes... which present known problems in all those areas...

Luckily for us involved in aquaponics.... the surplus nutrient wastes from fish feed/wastes... generally provide all the nutrient requirements for plants.... constantly replenished...

Deficiency issues in aquaponics almost always are a result of pH lockout of trace elements.. particularly iron, to some degree calcium, potassium.. and very, very ocassionally things like magnesium...

An initial water analysis of your source water might be beneficial... and certainly regular testing of your system parameters is advisable when beginning...

But your senses... eyes, ears and smell... will identify any signs of potential problems/deficiencies... as your experience evolves...

Get a regular API Freshwater Master Test Kit... and an Iron test kit if you wish.... and a salinity refractometer... and that's all you will need...

Plants have stages of growth where relationships between nitrogen, calcium, potassium and even phosphorus are important...

But nitrogen and phosphorus abound in aquaponics... due to fish metabolism and wastes...

And Calcium and Potassium issues/requirements are easily dealt with as a direct result of inevitable pH buffering adjustment...

Iron may need some supplementation if pH is above 7.2... by addition of chelated iron...and general trace elements can be supplemented by occasional/regular small additions of seaweed extracts.. Seasol or Maxicrop... (you can even get Maxicrop + Iron)

Rupe - why do you feel a need to attack anybody who has the slightest interest in quantifying what is going on in their system? You jumped all over me when I asked about phosphorus testing - and to be honest - your attack left me not wanting to be involved with this forum. I know you're a moderator, but that doesn't give you carte Blanche to act this way.

Huh?... sorry Smatthew... not sure what/who you think I'm attacking... and I'm sorry but I don't remember the "phosphorus" post...

I sometimes just write as I think... in between other things... it might be short... but it isn't usually done with any great emotional attachment...

P.S... just for info... I'm not a moderator, and never have been...

Just as well I haven't replied to TCL's post I guess..

The Above seems (at least I expect it does to some people) rather at odds with what is below.



If you are not testing and can't quantify what the levels are in a system that is growing well compared to a system that is struggling, How can you really claim that the hydroponic baseline recommendations really apply to aquaponics?

It isn't that I'm saying the plants don't need the same things, it is more that I'm saying the forms in which the nutrients are supplied in standard chemical hydroponic nutrients is not necessarily the same as the forms in which they are available in Aquaponics or bio-ponics and therefore the baselines might not really be 100% comparable. Kinda like the whole debate about taking vitamins or getting your nutrition from your food. Yea the lab test says this vitamin has x amount of calcium but does the body actually absorb the calcium well in that form?

And like you say Rupe, you are not testing all those nutrient values to make sure they match the baseline recommendation for hydroponics, you are trusting aquaponics to supply most of what is needed and supplementing as necessary where deficiency or pH shows the requirement. If you haven't done extensive nutrient testing/analysis on a system growing healthy plants, how do you know that the aquaponics system is supplying all the nutrients at similar test levels as would be expected in hydroponics?

I've heard so many stories of systems that are working very well and growing wonderful plants that have nitrate levels far lower than anyone would ever dream of running their Hydroponics systems at and I've tested for phosphorus in my AP systems and seen rather low levels compared to a hydroponics recommendation for growing lettuce but I'm not seeing any signs of phosphorus deficiency.

Only things I seem to be struggling with lately as far as nutrients go seems to be potassium and I haven't been able to find a good recommended potassium test kit so I can't really even say how my actual potassium levels compare to the recommendations for hydroponics.

As for Iron, A test kit for that might be worth while just to keep one from risking wasting money by over dosing expensive chelated iron. It is possible depending on your source water and your fish food to find that even at a pH of 6.5, Iron can get used up. In my system even with a pH of 6.5, and feeding Aquamax 4000, I need to regularly dose with DTPA chelated iron to keep enough iron in the system to avoid iron deficiency. I usually only dose up to about 2.5 ppm and that seems to work just fine to keep the plants happy even though the hydroponic recommendation says it should be 5 ppm.

So is it that my plants just didn't read the right books in school? Or the Hydroponics recommendations don't 100% apply exactly to the forms the nutrients are available in Aquaponics?

Hadn't got around to replying to your other post yet TCL... and it's bedtime... 02:30...

Not sure how my post to a direct answer to CDM has been interpreted as "at odds" to the questions you raised TCL, or the above post.... the context is IMO quite different... and IMO there's a difference between backyard and commercial production contexts...

But I'll respond tomorrow... and address the various points.... even at the risk of cruxification...

Seeing as my original answer was to CDM (original poster) asking about testing for everything and taking the guesswork out, I was kinda taking all the answers as general and related.

To me the lines between backyard/small farm/commercial are a bit blurred I guess since it seems many people use one to move on to the next or at least use backyard to learn enough so they can better decide if they even want to move on to farming or doing it for a living. And then of course those who do want to get really technical about it are going to have to go to more "commercial" or "academic" sources of information to get the recommendations of what the nutrient levels should be for growing different crops.



Why would they be any different for Commercial aquaponics than they are for backyard aquaponics?
Well they arn't but as noted, for backyard aquaponics it is usually not necessary to test all the different nutrient levels.

smatthew i actually think the discussion is a good and open one ,no attacks , Rupe talks straight ,i like that.