This page is a collection of good stuff

I feel strongly that I have the Perfect System design for any climate.
CLICK HERE for the details of that post.  
I will continue to update that article as I learn more so check it every once in a while.

But be sure to take advantage of the links below.  These are the gems I've found.

    Breeding Fish 
  •  Jon Parr (LINK) - I assume you have blues, Bob V? Blues will breed at 8 months, mossambicus at 3 months. Water temp needs to be above 80, and a water change always triggers a spawn. Feed them constantly, as often as you can, a belt feeder is best. First time mothers often have small batches, 25-50. Seasoned girls have 300-500 eggs each time, and 500-1000 for older bigger mothers. Ken, over 1000 eggs is pretty rare, but 2500? Maybe if your mothers are 3 or 4 lbs, but not 8".

    Bob V, size doesn't dictate sex, especially with young tilapia. In my experience, the first male to hit 2" becomes dominant, and all he can do is dance for the ladies. His focus is so intense, that ge will neglect eating, and invariably another male will pass him up sizewise and take over the lead role. Once a female starts breeding she doesn't grow much more, or grows very slowly. If you want bigger females, keep them from breeding by segregation or water temps below 75

  •  Vlad (LINK) - ...Things are way, way too wet. Stems, leaves, crowns the works. Next time one of your seedlings flops over, carefully excavate the hydroton or rockwool around the area where the stem meets the roots (called the crown). You will in all likelihood notice a 'thinned out' portion of stem there. Like the outer layer of the stem has been 'eaten' away leaving only the stringy inner vascular tissue. Don't bother looking at the roots, as that type of rot can only be observed later when the plant is a bit more developed. That type of thinning, wilting and flopping over of seedlings is caused by Pythium, a big lover of overly moist conditions and one of the most economically devastating oomycetes (pythium was long ago mistakenly classified as a fungus, and some people/books still call it a fungus for some weird reason) of soil-less growing (but in soil too...).
    I've not ever had much luck starting any plants off directly in a DWC set up, because of Pythium wilt. So I start the off in net pots and hydroton but NOT in a DWC bin trough. I give them a week and a half or two, then plop them in DWC. This has worked out much better for me.
    Your rockwool cubes look totally soaked as well, and it's a very, very bad idea to have wet leaves close to any type of light, or even lights on while leaves are wet (though flouros that are too far away anyways, would probably be the least harmful scenario, still not good though)...

    Ceramic Metal Halide Lights
  • Jon Parr  (LINK) - .CMH (Ceramic Metal Halide) are not necessarily the best, but they are my favorite. MH (Metal Halide) emit blue light for veg, HPS (High Pressure Sodium) emit red light for flowering, and CMH emit full white beautiful spectrum, including UV. Photosynthesis uses a fairly narrow spectrum of the blue and the red, and non at all in the green, in fact reflecting it, which is why plants are green. The jury is still out on how exactly UV is used, but side by side comparisons show healthier plants when a little UV is added, IDK. I do know that HPS are cheaper, about $20 and on the shelf at Home D for a 400W, as opposed to $50 for a CMH 400W. Bob, and Kevin, you will be amazed how cool HID lights are compared to flouros. The bulb itself is hot, yes, but the total heat generated per watt is less, and a vertical CMH bulb needs no cooling at all, not even a fan, as the natural convection draws a cooling air current upwards past the bulb. I pay $.45 per KWH, so efficiency is paramount, meaning no reflectors or glass to suck lumens. I hang a vertical bare bulb, and situate my plants around it in zip-grow style towers. Ideally, I don't want a single photon striking anything but plant. Is the UV dangerous from a CMH? Yes, probably, just as dangerous as it is from the sun. I have never noticed any discomfort, but I am in the sun working every day anyway. I've read that sensitive people advise wearing sunglasses, long sleeves, or even sunscreen if working around bare bulbs for extended periods of time. I have them lighting up my whole shop, but they are in closed fixtures with a glass panel, which blocks the UV.

    I get my CMH here, and ballasts, and sockets are available for about $15 at your local head shop. For flat grows like Bob and Kevin have, you'll want to add a wing style reflector to bounce light back down to the plants. The linked site also show some pictures of failed bulbs, and how the arc tube remains contained. The Phillips brand they sell are rated for open fixtures, a big plus for bare bulbers like myself.

  •  TCLynx (LINK) - Bottling pee and waiting for the enzymes to turn the urea content into ammonia can take a while.  In the Liquid Gold research I did a while back I found sources that said to bottle the urine until the pH got over 9.  This was usually the indication that the urea had converted to ammonia.  How long this takes can vary but 3 weeks seems pretty common.
    If you use the urine sooner, like perhaps you have it bottled for only 5 days or something, you may test and get an ammonia reading but that reading will only be telling you how much has converted (not how much may be left to convert) so if you were to dose your system with minimally aged pee, the ammonia levels could continue to rise after dosing and this could make figuring out your next needed dose difficult.

  •   Test Kit Longevity
    Vlad Jovanovic - Reagents can go bad after a while
    According to API :
    Ammonia Test Solution # 1 - 3 Years
    Ammonia Test Solution # 2 - 3 Years
    High Range pH Indicator Solution - 3 Years
    Nitrate Test Solution # 1 - 3 Years
    Nitrate Test Solution # 2 - 3 years
    GH Test Solution - 3 Years
    Calcium Test Solution #1 - 3 Years
    Calcium Test Solution #2 - 3 Years
    Phosphate Test Solution #1 - 3 Years
    Phosphate Test Solution #2 - 3 Years
    Copper Test Solution - 3 Years
    KH Test Solution - 4 Years
    Nitrite Test Solution - 4 Years

  • Testing pH
    Vlad Jovanovic - Eric that's a really good question. Just FYI though, in terms of the "false low" pH reading that you get right out of the's the CO2 trapped in the water that is the culprit and not Cl. (Eric, Cl has a pretty high pH of 11 point something, so it could never be that. It's good to off gas Cl for other reasons though).
    Carbon dioxide is only water soluble when pressure is maintained (like in your water pipes). In this dissolved state it is called carbonic acid H2CO3. Since it is a weak acid, when you measure water right from the tap without letting it sit out for a day or so, it will give you a false low pH reading. Once the the carbonic acid has a chance to off-gas into CO2, and escape into the air, you can only then measure the pH and confidently obtain a realistic reading. The difference is pretty big too. One to one and a half pH points (or more) is no small matter. If anyone cares this is the relation...

    CO2 + H2O --> H2CO3
    After that the carbonic acid reacts slightly (and reversibly) in the water to form a hydronium cation H3O-+ and the bicarbonate ion HCO3-
    H2CO3 + H2O --> HCO3- + H3O+
    This is also why when you open a bottle of distilled water, first you can't zero in on a reading (distilled water having no ions and all, and therefore no determinable pH. But, then as the distilled water reacts with the CO2 in the air pH you can hone in on a somewhat stable reading and will always get an acidic one (barring any other contaminates). This caused me no end of grief for a few days a good while back in my college days...having always heard, and believed, that distilled water has a pH of 7...This is not true. the pH of distilled or demi water is "indeterminable"...Anyways.............
    The chemistry probably only interest Eric, but anyone reading this (ever) needs to know that you have to let your sample water (tapwater, well water...anything that's been in a pipe or through pipeworks) sit out for a day or so before testing it's pH. If you don't, in a day or two you'll be scratching your head wondering what is causing your waters pH to "rise"...

    Comment by RupertofOZ 
    How do I keep my ph down keep going up to 8.2 no matter  what I do.  I change all the water and  clean all the clay balls

    Kurt, you need to understand what's causing your high pH in the first place... and why the pH bounces back even after a treatment with acid....
    The problem relates to a high carbonate buffering capacity... in your source water...
     Treating the tank volume with acid... apart from being potentially dangerous if you have fish in it... is like pushing marbles up hill with your nose...
    Yep, you'll see the pH drop when you first add the acid.... as it initially consumes some of the carbonate buffer in the water...

    But having done so...i.e the acid is neutralised by the remaining carbonate content.... the pH then just rises back to where it was... usually within a couple of hours...
    Continuing to treat with acid... will see the same thing occurring....
    UNTIL.... all the carbonate buffer is exhausted...
    Which would occur.... IF you did NOT add any further water... i.e "top ups".... OR a water change....
    Because your source water is high in carbonate buffering capacity.... changing water, especially changing "ALL" the water... is just negating any effect that adding the acid might have acheived...
    i.e... lowering the carbonate buffer....(somewhat)..... but just adding more carbonate buffer back to the system.....
    DON'T try and treat your tank volume.... treat your top up water... to the pH you want (even if requires several doses)....
    Doing so.. means that you wont be adding carbonate buffer back to your system.... and with nitrification.. and treated top ups.... your system pH will fall over time...
    DONT use lemons, vinegar, limes etc.... apart from the potential anti-bacterial properties... you'll need a truck load to have any effect... or at least any lating effect.... (lots of cost).... and meaningless if you don't treat your top up water....
    Use Hydrochloric acid.... it is simply the cheapest, most effective... and recommended (for several reasons).. way to lower the pH....
    Your high carbonate source water.. will actually be beneficial... eventually... when your pH has fallen to the point that it requires buffering upwards...
    As all you'll need to do... is top up with some "untreated" carbonate buffered source water..

    Winter Garden
  • Comment by Chris George 
  • shelfponics system outside has been up for about 2 years now...we have such mild winters here in Scottsdale, I haven't ever enclosed it or protected it...I have grown arugula, lola rosso lettuce, basil and spinach.  I have an urban farm, so AP has not been my priority the last couple of years, installing fruit trees, grapes and berries (all the perennials) was/is my focus and raising my chickens up from chicks.  To add to that, I have never tested the water, or adjusted the PH, or cleaned the hydroton media, or done one water change.  I feed the fish once a day (like I do in my small wildlife pond) and we all go on with our lives.  I had an aquarium AP set up inside for 6 months or so with strawberries, (in the kitchen), I tested the PH on that system, and the PH adjusted itself after awhile.  All of these are with 'feeder' goldfish, from a good aquarium store, they grew big and beautiful and some look a lot like koi.  Any cold weather vegetable (ones that you eat the leaves of...kale, lettuce, spinach, bok choy, etc.) will do great outside in the winter, until a hard frost, but things like kale actually don't mind a little frost, and it makes them sweeter...  Strawberries are great, too.  I want to try growing alpine strawberries from seed...they are so fragile when ripe that they don't make it to market...and if you find them at a farmer's market they are prohibitively priced.  Dennis at gardenpool has grown beets in shelfponics, not sure how long they took but they look hilarious when they are growing, the entire bulb (beet part) and greens grow above the media, only the tap root into the hydroton, and it grew to full size, 3-4" around.  Broccoli rabe is another choice, and mustard greens, I'm not big on either, taste wise though.
    Comment by Jon Parr 
    Bob, happy to help. For fall/winter, I grow chard, spinach, beets, peas, cabbage family (Chinese broccoli does killer, and is a staple in stir fry), lettuce, carrots, potatoes, onions, and others. Trout and sturgeon (this winter all outdoor water will be sturgeon and Kokanee for me) continue to feed all thru winter
    Seaweed Extract

Comment by Vlad Jovanovic 
Hi'd be very hard pressed to find any seaweed extract anywhere without a bit of arsenic and/or heavy metals...As bad as GrowMore Organic Kelp may seem, it still has 3.5 times less arsenic than MaxiCrop, and 4 times less lead...The brand Kelpak has by far lowest numbers in this regard (heavy metals, arsenic)...
I think a lot of it just has to do with the way in which we treat our Oceans (which is a fucking catastrophe), and where in that mess the kelp is grown/harvested.
@Larry casa...neither MaxiCrop, Seasol, or Kelpak are a major source of macro-nutrients Nitrogen-Phosphorous-Potassium (nor should they be)...Their whole "charm" is the fact that they are chockfull of plant hormones...mostly auxins and cytokinins. These are often labeled as "bio-regulators", since people seem to have an aversion to the term 'hormones'. And also, that they are full of trace elements. N and P aren't even in the whole numbers range (0.1 and 0.4) and K is at 1% ...So in a new system (all things being relative)...sure, it can be looked at as a "big" source of potassium...maybe enough for leafy greens and whatnot...but again, the trace elements and bio-regulators/stimulators are the main gig there...

Comment by Bob Campbell 
@Vlad Jovanovic - I found this in a 'The Manufacture and Propertiesof Liquid Seaweed Extracts'
The recent revelopment of seaweed research in Chile has given three
very interesting papers on the effect of seaweed on calcareous soils
1966). The first paper showed that additions of seaweed significantly increased both the «available» potash and nitrogen in the soil. The second
paper used additions of seaweed to incubated soil samples and
demonstrated an increase in «available» phosphate. These experiments
also showed that small additions of seaweed (0.38 %) produced more
«available» phosphate than larger additions (1 %) and concluded that
the effect was due to microbial action stimulated by the seaweed ; this
result recalls my own experience with a similar soil in 1958. It may
be added that similar results are obtained with farmyard manure and
the latest work on this topic (SALTER & WILLIAMS, 1968) makes the
observation that «... over the period of the experiment large increases
in exchangeable phosphorus and potassium were obtained on plots which
had received farmyard manures. The better effect from small quantities
of seaweed recalls some earlier work by SENN et al., who found 250 lb/
acre gave better results than 500 lb/acre ; similar results are common
with seaweed extracts where a dilution of 1/2001 or 1/300 is usually
more effective than more concentrated sprays. The third paper from
Chile describes the effect of the brown seaweed Macrocystis integrifolia
on the availability of iron in a calcareous soil and used soil samples
incubated with seaweed, ferrous sulphate or alginic acid. The mixture
of soil and seaweed gave the highest level of «available» iron, alginic
acid was less effective and the addition of ferrous sulphate was ineffective.
Calcareous soils present unusual «availability» problems and
these effects on the «availability* of iron and phosphorus are worth
further study.

Comment by Scott Bloom 
Purslane contains more omega-3 fatty acids (alpha-linolenic acid in particular[4]) than any other leafy vegetable plant. Research published by Artemis P. Simopoulos states that Purslane has 0.01 mg/g of eicosapentaenoic acid (EPA). This is an extraordinary amount of EPA for a land-based vegetable source. EPA is an Omega-3 fatty acid found mostly in fish, some algae, and flax seeds.[5] It also contains vitamins (mainly vitamin Avitamin C, and some vitamin B and carotenoids), as well as dietary minerals, such as magnesiumcalciumpotassium, and iron. Also present are two types of betalain alkaloid pigments, the reddish betacyanins (visible in the coloration of the stems) and the yellow betaxanthins (noticeable in the flowers and in the slight yellowish cast of the leaves). Both of these pigment types are potent antioxidants and have been found to have antimutagenic properties in laboratory studies.[6]
100 Grams of fresh purslane leaves (about 1 cup) contain 300 to 400 mg of alpha-linolenic acid.[7] One cup of cooked leaves contains 90 mg of calcium, 561 mg of potassium, and more than 2,000 IUs of vitamin A. A half-cup of purslane leaves contains as much as 910 mg of oxalate, a compound implicated in the formation of kidney stones, however, note that many common vegetables, such as spinach, also can contain high concentrations of oxalates.
When stressed by low availability of water, purslane, which has evolved in hot and dry environments, switches to photosynthesis using Crassulacean acid metabolism (the CAM pathway): At night its leaves trap carbon dioxide, which is converted into malic acid (the souring principle of apples), and, in the day, the malic acid is converted into glucose. When harvested in the early morning, the leaves have ten times the malic acid content as when harvested in the late afternoon, and thus have a significantly more tangy taste.

Purslane (Portulaca oleracea), raw, fresh,
Nutritive value per 100 g.
(Source: USDA National Nutrient data base)
Principle Nutrient Value Percentage of RDA
Energy 16 Kcal 1.5%
Carbohydrates 3.4 g 3%
Protein 1.30 g 2%
Total Fat 0.1 g 0.5%
Cholesterol 0 mg 0%

Folates 12 µg 3%
Niacin 0.480 mg 3%
Pantothenic acid 0.036 mg 1%
Pyridoxine 0.073 mg 5.5%
Riboflavin 0.112 mg 8.5%
Thiamin 0.047 mg 4%
Vitamin A 1320 IU 44%
Vitamin C 21 mg 35%

Sodium 45 mg 3%
Potassium 494 mg 10.5%

Calcium 65 mg 6.5%
Copper 0.113 mg 12.5%
Iron 1.99 mg 25%
Magnesium 68 mg 17%
Manganese 0.303 mg 13%
Phosphorus 44 mg 6%
Selenium 0.9 µg 2%
Zinc 0.17 mg 1.5%

System Design Considerations
Comment by J. Linden Rose on August 31, 2012 .
   Many people use gallon of fish tank to gallon of grow bed ratios. This has a minor flaw, because nutrient uptake and removal by plants is directly related solar surface area, and only indirectly related to grow bed volume assuming root development plays a large role in your particular crop. But before you can say something like 3 sq. ft. of grow bed per gallon of fish tank, you need to think about stocking density and feed conversion ratio (FCR).
   In this industry everyone is taught to sell their tilapia when they are no more than a year old. The reasoning is that when fish are small and young, the FCR is smaller, and less feed becomes more fish faster.  That's useful thinking in the aquaculture world, but lacks a certain breadth of consideration in the AP world. You might consider an aquaculture strategy that focuses on growing larger, older fish.  Remember that AP systems produce about $4 of produce for every $1 of fish in a Rakocy style system which has been optimized around fish production.  By lengthening the grow-out period for your fish, the FCR will increase, but it will also stabilize allowing you to have better control over the nutrient stream to the much more important produce side. Additionally, higher FCR means more nutrients end up in the plants than in the fish... which is where the money is. This in turn should imply that larger fish lead to larger grow beds.
   With that in mind, its probably a good idea to see your system as one that will go thru many changes when it is new. Then as your fish mature, and your nutrient stream stabilizes, you will be able to fine tune the grow bed surface area to match.
   Gravel beds, a type of fluidized bed reactor, are the oldest and most established form of modern aquaponics, and were first used in the work of Woods Hole researcher John Todd at his New Alchemy Institute, and Dr. Mark McMurtry at NC State.
   Dr. Jim Rakocy, a RAS (Recirculating Aquaculture Systems) aquaculture specialist at the University of the Virgin Islands in St. Croix, abandoned gravel beds because he wanted to work around the issue of sludge build-up. To avoid sludge issues, he developed raft culture, which in the absence of a bed reactor, required settling and degassing tanks. This system falls short of optimal for several reasons: 1) you're spending money on nutrients your plants need that you then remove from the system wasting resources 2) his floating rafts blocks most of the air-water interface for gas exchange intensifying the need to waste electrify on compensatory aeration, and 3) this system design is fish-centric, obsessed with how many fish you can cram into a barrel, when Jim's own publications showed that the aquaculture side was a minor contributor to revenues, and 4) only a very limited number of plants can tolerate having their roots immersed in water 24/7.  Typically plants with low nutrient requirements and low ability to scrub nutrients from the water.
   Tom Speraneo, is credited with the first use of tilapia in AP systems, but also is credited with cycling the water level in the gravel beds, creating enormous amounts of temporary thin water surfaces for gas exchange, and facilitating aerobic RAS waste processing. But the other interesting development was that it made the beds capable of sustaining active vermiculture, which further breaks down and decomposes the solid wastes, and restores lost nutrients instead of wastefully removing them.  This seems to have been confirmed by the systems popularized in Australia by Joel Malcolm and Murray Hullam, with Murray claiming to have systems that have run without any waste removal being necessary for over 3 years.  Similar results have occurred in Hawaii with Glenn Martinez's system.
   Using the archaic meaning of vermiculated of "worm eaten", we can call these vermiculated fluidized bed reactors, and their use should free up a great deal more nutrient from the same amount of feed input, allowing you to focus on the much more profitable produce production side of an AP system.
   With that in mind, Wilson Lennard has shown that raft cultures seem to be slightly more productive with low nutrient crops like lettuce, whereas most crops cannot be grown in rafts at all.  Since lettuce has a very fast seed to crop cycle, it can provide stead cash flow while waiting for more valuable crops to mature in the gravel beds, and with all the extra nutrients available, there's plenty of reason to have both in your system design.  This will also increase the total system volume, which is good for fish, and if you design your deep water wells with tops that are not floating on the water, you'll have greatly enhanced gas exchange surfaces.
   It would probably be a good idea to avoid NFT (Nutrient Film Technique) completely if your system includes fish production, because a thin layer of water spread out over long distances is basically a heat exchanger, which will cause diurnal temperature swings in your fish tank greatly adding to their stress levels.
Comment by Glenn Martinez on September 1, 2012
   First, most of us have fallen into a trap of running our aquaponic (AP) systems 24 hours a day. Think again....perhaps it should be shut down at night, drain the bio-filter (cinder beds) and let the system rest at night. Keep pumping the AIR to the fish, but stop running the water thru the vii-filter and float beds. This saves energy. It also allows the fish water to build up ammonia that will then be sent the bio-filter beds. Very quickly the bio-filter will convert the ammonia to nitrates.
   As long as you do not let the ammonia build up in the fish tank, you are okay. It is recommended drain the bio-filter bed when it is not circulating, as leaving water stilling in the bio-filter, seems to deplete the oxygen (everything is composting) and kills the worms and oxygen loving bacteria....
   The worms in our AP systems (cinder beds) eat the fish solids, breaking them down. Most important to keep in mind that our siphon system is NOT inside the bio-filter, but removed and located in an container that will drain the vii-filter "drip dry" at each flush. All of our bio-filter beds are "double tray" or false bottom, to allow drip dry draining. The drained bio-filter bed will NOT dry out over night and the plants do not suffer.
   To drain the bio-filter beds at night, place a small hole in the stand pipe of the bell siphon or install a small drain tube to drain the bio-filter bed when the water stops coming in for any reason , like a power failure.
For balanced nutrition, add vermicast or compost tea. That will supply all the micro and macro nutrients you need to grow NUTRITIOUS food, kala etc.
Food for thought.
Glenn, Olomana Gardens, Hawaii
Comment by John Burgess on October 17, 2012

   "To drain the bio-filter beds at night, place a small hole in the stand pipe of the bell siphon or install a small drain tube to drain the bio-filter bed when the water stops coming in for any reason , like a power failure."
Just run a standard overflow standpipe... and timer... flood & drain configuration... ditch the siphons altogether...
   Part of such a configuration... is the (generally) two small (6mm) holes at the base of the standpipe.. to allow the grow bed to "drain" during the timer off period...
   And utilising a timer based F&D... means it's simple as... to turn the beds off or limit/extend the F&D cycles.. during the night... or as a response to climatic variables...

Comment by Nate Storey 
RAS (Recirculating aquaculture systems) sludge can't be used in hydroponic production- the oxygen demand is too high and you'll have issues with anaerobic conditions in your root zone.  You can use it for direct application to soils.  We have used heavy sludges in vermicomposters that we then use to supplement our germination mixes and plug production.  It's acts as a nice slow release fertilizer in these applications.

Note by Bob Campbell:
I have tested sludge to see if it has any extra Nitrate.  It does not have any extra Nitrate 

Vlad Jovanovic yesterday I've seeded and grown out thousands and thousand of plants in two inch net pots filled only with hydroton. My germination rate is quite high using hydroton only. There might be some old pics on my page here...or somewhere. But basically, like Devoid, I built a 4x8 table (lined it with Duraskrim) and plumbed it to a trough). A pump on a timer floods the table with an inch and a half or so of water.... as often as is necessary according to what season it is (temps/humidity). There is a short standpipe (that keeps the water level at about 1.5 inches)...when the pump stops, the water drains back into a DWC trough via two small holes near the bottom of the standpipe... From here, these rafts get transferred into a nursery trough that has about 8" of water. From there the net pots get taken out of this tight spacing and transferred into production rafts (regular 'ol 2' by 4' rafts with 8" on centers hole spacing)...

That's about as efficient as I could get it using these materials, guys. I'm not real keen on using vermiculite within the system, as it tens to break down and get into pumps and other things. I try very, very hard to keep foreign particulate matter of any kind out of the system. I feel that, that is a wise strategy in the long run...but to each their own For media beds, I pretty much just do what Alex does (except of coarse for the crazy dual root zone thingamabobbers that I have going on)...

Hi guys...the chart that Jim posted actually applies to soil gardening and not hydroponics (or any other type of soilless culture). It is common to mistake the charts as the two are often floated around "internet-land" rather indiscriminately :)
Most (decent) soils have a vastly different cation exchange capacity than most common soilless mediums...or "worse" yet, water culture (as in a DWC scenario, this is why, in part, in a low nutrient density environment, or one where pH is rather high, plants in the DWC portion of a system tend to exhibit visual signs of deficiency before their counterparts that are in a media filled grow bed...even though they are in the same system) below are two charts (soil vs soilless) for comparisons sake...
 Notice that the soil chart is much more forgiving...
Oh, and no...there is nothing "magical" about AP. How plants grow without soil, is how plants grow without soil. That said, a well seasoned, mature, micro-biologically thriving AP system seems to display more of that "soil like" forgiveness, that a new or micro-biologically sparse one (much of this seemingly has to due with niche nutrient cycles beyond ammonia oxidation) .


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