Backyard Aquaponics
A place to discuss aquaponics

I totally agree...now
Also agree on the worm stocked system to help speed mineralization.
I would have liked to find out how much phosphorus actually ends up back in solution of the water ie phosphorus cycle??...but without that knowledge running the feed back to all the growbeds and having worms in the growbeds as opposed to seperate worm bed is best way to go because I understand that phosphorus isn't as soluable as nitrates.

Not trying to pick a bone with anyone... I'm saving them for the AP system

I did a Phosphorus test today on my AP system. Phosphates are 5 ppm, the second highest level on the test. Most AP systems don't bother testing for phosphates. I imagine that if more people did test for it, it would be common place to find systems running with high phosphates. Not a problem for AP as it would just provide more nutrients for the plants.

The only way that so much phosphate entered my system is from the trout food. Also note other nutrients are high as well. Nitrates 160 ppm (the highest level on the test).

They do make phosphorus tests for aquarium and pond so if one wants to track that it's easy.

I will say that one should NOT try to add phosphates to their AP systems unless they 1, get a test kit and confirm that phosphorus is lacking in their system and 2, they see signs of that lack in the plants.

Just like with nitrates. I've heard people freak out and want to add more nitrates to their system because the test kit shows low levels but I say to them no, not unless 1, the test kit reads 0 and 2, the plants are showing signs of nitrogen deficiency. Many people run AP systems that grow great plants and veggies and yet, their systems are so well balanced that they don't show any Nitrates according to the test kit.

If your system is still really new, don't go adding a lot of extra stuff. A dose or two of seaweed extract is probably all it needs and mucking around with lots of extra stuff is more likely to upset things and cause a crash than to help the plants. This isn't Hydroponics, you need to let the system get into balance and let the bacteria feed your plants. Don't expect the first season to out perform, you are still building your bio-filter.

Bumping an old thread here..

Just tested my phosphorous levels in one of my AP systems here (with an API phosphorous test kit)

Got a reading of 2ppm.

I haven't supplemented.

What's the desired level of phosphorous we should be aiming for in fruiting AP systems?

thanks

Wowsers.. think I just found my answer off Nate's website:

"For most aquaponic systems shoot for phosphate concentrations between 10 and 20 ppm for light feeders (vegetative crops) and between 20 and 40 ppm for heavy feeders (tomatoes, cucumbers, etc.).

Note: If you plan on running higher levels of phosphate in your system, prepare to supplement other nutrients at higher levels to balance your solution out."

http://verticalfoodblog.com/phosphorus-in-aquaponics/

That seems pretty high, particuarly seeing that I have been feeding quite heavily twice a day in this system and only have 2ppm.

I think I will try supplementing phosphorus in my fruiting system (using rock phosphate) and see how it goes. I have my fish tank fairly well shaded which should help the tendancy for algae blooms with higher P levels

any thoughts or advice?

thanks

I generally trust the information that dude provides but i dont agree that those ranges are really necessary.. remember that you are feeding fish daily and adding phosphorous constantly.

did you watch the video or just read the summary? because the dude only recommended adding phosphates to systems that only grow fruiting plants. and he talked for a good portion of the video about adding the supplement in a way that it is uptaken by the plants as fast as possible so there is not a storage of P available in the water.

Like tclynx has said a few times, do you see any evidence of phosphorous efficiency? purpling of leaves maybe?

Yes I have watched Nate's video a few times, and read the writeup.

Yes, this is for my fruiting AP system only (mainly tomatoes and cucumbers)

How much phosphorus is there in the fish food? I guess it depends on what brand etc right? I'm using Lucky Star, the bag has chinese writing all over it. I'm not going to use it again as I don't trust it

Don't burn me at the stake for heresy - I'm actually trying to take some of the voodoo out of AP by closely watching nutrient levels

My plants are not purple, but are not thriving with fruit growth.

I have already supplemented Iron and Potassium so am now focusing on phosphorus and calcium to see if thats where my problem lies



What are you basing this off? Got a link?

In a system where the solids are removed this would be true.

We seem to be on almost identical journeys Jono! Since finding out about the 'hidden hunger' of potassium whereby plants will NOT show a deficiency but growth will be significantly effected, I started wondering also if P was limiting my fruiting plant growths but not showing signs of deficiency - maybe these only show in acute circumstances rather than chronic. hence my post on nutrient profiles.
viewtopic.php?f=1&t=20752

I too wanted to start getting a bit more 'quantitative' in calculating inputs and outputs and required levels. However, I believe before being burnt at the stake though, we should at least be tested to see if we float. If we do in fact float, then its perfectly acceptable to go on to the stake burning stage.

Yep..

I've tried a couple of years now growing tomatoes and cucumbers in AP with mixed results. It always just seemed so hit and miss. I wanted to know why. I was always feeding good quality feed, regularly, and not removing solids.

I started supplementing Potassium (in addition to the normal iron and calcium) and now I'm finally seeing regular, repeatable good fruit growth

I've also installed quite a few AP systems now for customers, friends and family. A trend I have noticed with these systems is no fruiting plants seem to do that well at all until at least 6 months in, and even after then, the most common complaint seems to be why won't my plants set fruit etc etc

Jono hi.
not because you aren't removing solids doesn't translate to mineralization of the solids. it's similar to composting. we can have a lot of clipping spread out on a field but it never seems to decompose fast enough.. but that same amt of clipping put together in one pile will decompose and a matter of days. so back to aquaponics its not how much solids u have in your system it is, where are these solids concentrated within the system to allow for the bacteria/microbes/bloodworms to cultivate and breakdown to solids into useful forms. and there is where proper design comes into play. think about it and see if I'm making sense. happy growing.

Sent from my SM-N900 using Tapatalk

The major reason that decomposition of organic matter spread accross a field does not occur is most likely to be moisture related. For things to rot they must be damp. So called "dry rot" of wood in buildings does not actually exist. Rather it is wet rot that when it has been found during renovations or building inspections has dried out.

In AP GBs moisture is not limiting and the study of similar components in the waste treatment industry and the field of environmental engineering is that such components are oxygen limited. Being only science and not mathematics it is possible that your theory that wastes decompose faster in a mineralisation tank but I don't know of any empirical studies where this has been specifically studied.

Having said that I do know of studies that have compaed the capacities of mineralisation tanks and reciprocating constructed wetlands and aerated constructed wetlands. Basically the information I have seen suggests that RCW and ACW equal or even succeed the capacity of mineralisation tanks and manage to do so using less electricity.

Having said that Ryan's MTs apparently use very little electricity but we don't know exactly what he is doing or how it would compare to the electricity use of a comparable RCW or ACW.

What test kit do you use? Does it report in P (Phosphorus), or PO4 (Phosphate)?