Hydroponic Plants: Tips, Suggestions, and Techniques?

[JMJones0424]

Yes, that's the fundamental problem with using organic nutrients in hydroponics. For organic nutrients to break down into a form the plants can use, you need massive surface area. Since the soil has been removed from the system, there isn't enough effective surface area to provide nesting sights for the bacteria to deal with the organic matter. As the organic matter sits in the medium, it causes small localized pockets of anaerobic zones, which encourages root rot, but more importantly, causes pH to rapidly fall. I have noticed a nutrient solution with reasonable water hardness fall from 5.6 to 3 pH overnight, which of course obliterated the plants in the system.

 

The aquaponics farm I worked at used flood and drain beds that the plants grew in, and used twice the volume of water in the grow out tanks of fish as a baseline for the amount of growing medium necessary (they used small gravel that had been specially sourced to ensure that there was no limestone containing elements in it, I still prefer lava rock). However, this was horribly insufficient, and the beds had to be flushed on a monthly basis to prevent organic matter buildup. UVI uses separate tanks filled with plastic netting that the effluent flows through first in order to remove the organic matter and bacterial action from the plant's roots, and this seems to be a much better approach. I have found for the hobby gardener intent on using organically derived nutrients, the most space-efficient means to accomplish this is to use a fluidized-bed filter, such as those used in saltwater aquariums.

 

This brings up another important point, and I have a hypothesis but have never been able to either verify it or devise a way to appropriately test it.

 

When plants are grown in soil, appropriate pH for most plants seems to be around 6.5 to 7. However, as one decreases the water cycling time, the necessary pH drops, all the way down to just above 5 in DWC. I believe that the plants actually take up nutrients most effectively at a pH of 5.2 or so, but in soil, in order to maintain 5.2 directly around the roots at a time when the plant is most biologically active (once half the water has been removed from the voids around the roots), you must first start with a soil/water mixture at 6.5 to 7. As the water level decreases, but the ion content remains relatively stable, the actual properties of the microscopic water droplets around the rootzone changes. TDS increases, and pH decreases.

 

However, the bacteria that break down organic matter seem to respond best to a neutral pH. Yet another reason why it is best to separate the breakdown of nutrients from the plants in hydroponics.

[Getting A Life]

JM Jones - outstanding! You have a fantastic grasp of how these things work I relate to so much of what you say.

 

I enjoy tinkering with aquaponics and would love to go to Virgin Islands but geographically and financially this is not a reality (for now). I am getting a lot of schooling in now though, as my endless nights of internet grazing were fairly fruitless as well.

 

I have a specific aquaponics problem, perhaps you can help.

 

Pond - 1200 litres.

Stocking density low - approx 1 kilo per 100 litres.

Aquaponic ebb and flow beds - 6 square metres. (1200 litres substrate)

pH - 7.2. Total Hardness 500 ppm.

 

The pH is the result of too much limestone as substrate, I have removed this but the pH won't budge.

 

So, I am considering adding CaOH.

 

Q 1. Is this (chemical reaction in water) harmful to fish?

 

Q 2. Is this the right approach?

 

I think the sums to calculate CaOH required would go like this. Can you correct me if I'm wrong please.

 

-0.4 = desired pH shift.

 

+0.4 = required hydroxyl ions.

 

Current H3O+ = 10^-pH = 10^-7.2 = 6.309573445x10^-8 mol L-1

 

Current H30+ mol L-1 x 1200 L = 7.571488134x10^-5 mol

 

Desired H30+ = 10^-6.8 x 1200 = 1.901871831x10^-4 mol

 

Current H30+ minus desired H30+ = -0.0001144723018 mol

 

To subtract the H3O+ equal portions of OH- are added.

 

So, 0.0001144723018 mol CaOH is required. Approx 1 litre of 0.1 mol solution.

 

This sounds very low, what have I done wrong?

[JMJones0424]

Ack, it's been a few years since I did stochiometric problems. However-

 

Everything in this post is applicable to aquaponics, not hydroponics

 

With a pH of 7.2 in an aquaponic system, the last thing you want to do is add calcium hydroxide. This will raise the pH. Not only will a higher pH inhibit plant uptake of nutrients, but also higher pH causes ammonium ions to convert to ammonia, which is highly toxic to fish. If you really wanted to tinker with the pH (which I don't think you need to do at 7.2 pH), you need to add either nitric or phosphoric acid, depending on the needs of the plants. If you wanted to raise pH, unless you specifically needed the calcium, I would recommend potassium hydroxide instead.

 

This being said, there are a lot of other factors involved that I barely understand myself. How long has your system been running? How high of a protein content fish feed are you using? Is there any place where galvanized metal or concrete is in contact with the nutrient solution/effluent? Are the fish healthy? What are the other parameters of the nutrient solution (EC, ammonia, nitrite, nitrate)? By "total hardness" are you referring to GH or "carbonate hardness" (KH)? If you mean KH, then 500ppm sounds extremely high, are you sure you don't still have a carbonate source somewhere?

 

For those not familiar with aquariums -

GH is a measure of Calcium and Magnesium ions, measured in German degrees. Multiply by 17.9 to convert to ppm. Test for calcium and subtract to get magnesium ion ppm. High GH is often referred to as "hard water".

 

KH, or carbonate hardness, is a measure of carbonate and bi-carbonate ions. These ions provide the pH buffer for the nutrient solution. Also measured in German degrees, convert to ppm the same way. If you have a high KH, the addition of acids will cause insoluble compounds to form and drop out of solution, lowering the pH.

 

Generally speaking, you want about equal amounts of nitrogen and calcium ions, with significantly less magnesium (perhaps 1/3 of calcium levels, but dependent on plant needs). However, calcium especially, and to some degree magnesium, is not readily used up by the plants, and I rarely ever needed to add more than the fish food itself introduced into the system after the system stabilized.

 

I think the most important thing is to first determine whether it is KH or GH that you are measuring, and then if it is KH, try to determine where you are getting carbonate ions from. Did you fully replace all the nutrient solution after removing the limestone substrate? Are you using tap or well water that has a high KH?

 

Chasing pH is generally counter-productive. If you have no problems with the components of the system, and you are only adding distilled or RO water and quality fish feed to the system, then it should eventually stabilize just under 7 pH. What ever you do- don't add CaOH to 7.2 pH nutrient solution!

[Getting A Life]

Thanks for that. I'll have to get out the test kits etc and take a good look at what I have.

 

A professor recommended the calcium - for forming a precipitate of CaCO3?

 

I know - ammonia 0 nitrite 0 nitrate 0.

 

I did not do a complete water change, but 4/5 of it got changed and it didn't make a difference.

 

Source water - all I know is 150 ppm and pH 7.0. I put this in a 100 litre container and refill pond from there. This is treated with 1:100 000 EM after dechlorination (waiting for it to offgas).

 

The fish are 3/4 omnivorous fed on cheap pellets duckweed algae and insects. The eel 'Achilles' is massive (about 3 kilos) and eats roast chicken and strips of beef. He's 12...

 

The problems I'm having, if this pH is not so bad, must be micronutrient deficiencies. However, best we get to the bottom of the hardness problem first, as this is likely causing the uptake imbalance.

 

I don't add extras (bar that limestone) and have never tried to 'fix' pH before, preferring nature to do it's thing. However, something is not right in this system, it's growth is very average and it used to be phenomenal, and I'm dead keen to understand what it is that might be fixed.

 

The system is about 4 years old. the pH has been 'high' for about 2 years. Should have left a good thing alone.

[JMJones0424]

An excess number of Ca ions is not desirable (for the plants). Your professor was correct, in that calcium ions will combine with the carbonates and precipitate out. But this is a two-way reaction that achieves equilibrium based on pH. If you add those calcium ions in the form of a HIGHLY basic solution such as calcium hydroxide, you may be removing carbonates, which resist pH drop, but at the same time you will increase pH. You need to buy a KH and GH aquarium test kit and determine the carbonate hardness and total hardness of both your water and your top-off water. If you suspect magnesium shortage or abundance, you will also need a FRESHWATER calcium test kit. KH should be no higher than 200ppm or so. If it is too high, do water changes to lower, and monitor. If your top-off water is also high in KH, then you will slowly accumulate excess carbonates, and will need to periodically do partial water changes, or add de-ionized water instead of tap water.

 

I suspect, since the system is 4 years old, that you may very well be experiencing micro nutrient deficiencies, but it is hard to tell. If you are close to the ocean, try adding a small amount (no more than a couple liters) of sea water. If this is not possible, add some liquified kelp meal.

 

Excess KH will not, to my knowledge, affect plant growth as long as pH is in an acceptable range (below 7.5) Excess GH can be detrimental, as the Ca++ ions displace other positive ions that the plants need like iron.

 

***

 

Stated in a different way, high alkalinity (high KH or "carbonate hardness"), is NOT the same as being highly alkaline (high pH). Nor is it the same as high "total hardness" (GH). It is confusing because the words are so close, and the aspects are inter-related, but the difference lies in what you are measuring. An ALKALINE solution has an excess of OH- ions. A solution with high alkalinity has an excess of either CO3-- or HCO3- ions. A solution with a high GH has an excess of Ca++ and Mg++ ions. Alkalinity is required for pH stability, but an excess will lead to a high pH and in certain species, health problems in fish. OH- ions are only needed to raise pH WITHOUT raising alkalinity. GH is needed to maintain adequate levels of calcium and magnesium for the plants, and is needed for shell formation for invertebrates and in salt water tanks for coral. If your pH read 5.5, and KH was 25ppm, you would want to add either calcium carbonate or dolomite lime (calcium carbonate with a small percentage of magnesium carbonate mixed in). If your pH was 5.5 and KH was 150, you would want to add potassium hydroxide. If pH was 5.5 and KH 25ppm, but GH was 300 (rare, but I have seen it in well water containing a lot of sulphates), you would have to add potassium bicarbonate.

 

Now, adjusting pH down is a lot easier, since natural biological processes tend to lower pH over time. (I can't remember for sure, but I think it has to do with the conversion of ammonium to nitrate) Your major choices are either HNO3 (nitric acid) or H3PO4 (phosphoric acid), depending on if you want nitrogen or phosphorus ions added to the system. For most fish, 100-200ppm nitrates is not a problem. High phosphates can cause algal blooms. But flowering plants would benefit from higher levels of phosphorous than typically found in aquaponic systems. Other options include citric acid (though it takes a lot to make a big difference), and making a peat moss "teabag" by stuffing peat moss into an old pillow case and tying the end, then placing this in the grow out tank for a time until you notice pH starting to drop (from humic acids). As long as you do not rapidly change pH, most fish can take a greater pH range than the plants and the bacteria necessary to process the fish waste. I wouldn't even bother messing with pH if it is between 6.5 and 7.5.

 

Also, you shouldn't have 0 ppm nitrate. Zero ammonia and nitrite, yes, but you need at least 10 or more ppm nitrate, preferably as much as 50 or higher. I have gone as high as 150 with no ill effects on tilapia. This is where the balance comes in between the plant's and fish's needs. If you are having problems maintaining nitrate levels, either reduce planting, increase fish load, or add hydroponic nutrients to the system. Metanaturals (if they are still around, haven't purchased them in a few years) makes an excellent line of OMRI listed hydroponic nutrients. They offer 12-0-0, 3-3-3, 1-5-5, and Calcium products, but they ARE NOT processed and plant ready, so you must have an active biological filter going in order to use them. I have used standard chemical salt hydroponic nutrients in small amounts with tilapia with no ill-effects, just stay away from anything with copper in it.

 

Are the omnivorous fish cichlids? They typically require a higher GH(?) than other freshwater fish. What symptoms are you observing on your plants? Does it appear to be iron deficiency? A high GH will prevent iron uptake by the plants. One way to get around unhappy plants without making fish unhappy is to foliar feed.

 

I could go on for days, but it's extremely hard to diagnose problems without seeing your plants and your system. Unless you can accurately determine KH, GH, and pH, I would suggest doing 50% water changes weekly and foliar feeding until you correct whatever imbalance is there. Playing with pH without also knowing GH and KH can be hazardous for both your fish and your plants.

[JMJones0424]

I think it is important to note during this little side-track into aquaponics that absolutely none of this is an issue in hydroponics.

 

If fish were not involved, one could deduce KH by observing pH fluctuations. In a hydroponic system, if one observes rapidly falling pH, it is almost always caused by insufficient aeration, and less likely caused by insufficient pH buffering (KH). You should check all root zones for foul smelling areas and check to make sure all air diffusers are working properly. Cheap aquarium air stones have to be replaced every six months or more often, while expensive ceramic ones can be cleaned when clogged and re-used. If anaerobic zones can be reasonably ruled out as the cause of pH drop, than it is safe to assume you have a buffering deficiency, so add potassium bicarbonate (or calcium carbonate if you think you need the calcium).

 

On the flip side, if you have a high pH, and you are using a balanced nutrient formula, then you are almost definitely experiencing high KH. Ensure that you do not have any limestone containing media in the system. (This can be done by placing a small amount of media in a glass and pouring vinegar over it. If it fizzes, than you have carbonates in the media.) If you can rule out carbonates, check all pumps to make sure that all seals are still in place. If pH is still too high, then slowly add an acid (preferably nitric or phosphoric) and observe pH 30 minutes after the nutrient solution has been circulated or well mixed. Observe pH again in 12 hours. If pH is steady, then no worries, if it is high again, then you have excess KH, and should replace the nutrient solution. Without testing for KH, there is no way to determine how much excess carbonates you have, and it is better to just start over with a fresh nutrient solution than to continue to dump in acids to fight high KH and inadvertently throw off N:P and P:K ratios.

 

With standard hydroponic nutrients, the less you add, the better. Manufacturers make many different kinds of additives that are marginally beneficial at best, and quite often detrimental except in very specific cases. If the only meters you posses are pH and EC, it is impossible to accurately determine N:P, N:Ca, and P:K ratios. The more "stuff" you add, the more you mess up the ratios, and the more likely it is that you will end up causing nutrient lock. If basic parameters are way off, it is far better to just dump and start fresh.

[Getting A Life]

Vinegar/medium test. No fizz except... stones at water line growing slime molds succeeded by mosses.

 

Things are cycling, and the lime below the water line doesn't seem to be in the medium any longer.

 

I cannot do a bunch of tests as I cannot afford a bunch of test kits (student). But would love to be able to follow your advice and get to the bottom of this.

 

The hardness test is 3 wee bottles, performed via titration, each drop representing 10 ppm. Ring any bells?

 

I've tried peat socks to no effect.

 

The plants display deficiencies, they never used to at 0 nitrate. I can add nutrients, I'd prefer trying seasol liquid seaweed before anything else - because I have some. I will also get some water changed out over time (I hate big changes in aquaponics) to remove hardness in this manner.

 

The vinegar:medium test revealed a very high population of worms. Oligochaetes, but small, up to 30 mm. Approx 1 per piece of lava rock. You mentioned a buildup of wastes and how a preferential system has the biological filter before the plants...

 

I see this working, obviously, but question the increasing complexity as it adds to labour and set up costs while providing the problem of solids to be dealt with. Aquaponics has fantastic potential, don't get me wrong here, I just think it needs simplifying. Returning wastes to the food chain appeals to me, but practically, can closed aquaponic systems be sustained in this manner?

 

What do you think of my concept of skipping all the fancy equipment and running a straight aquaculture facilty (with biological filters) that pumps its wastes mixed with water changes directly to an outdoor garden project.

 

I envision problems with biofilms clogging the irrigation system and altering the biology. Perhaps EM would keep things clean enough. It keeps drain pipes clear, I know that much.

[JMJones0424]

The hardness test is 3 wee bottles, performed via titration, each drop representing 10 ppm. Ring any bells?

 

Not particularly, the test kits I use are from aquarium pharmaceuticals, and both the GH and KH tests are one part titration solutions. You originally referenced total hardness, which is GH, and this has no direct effect on pH. It is generally safe to assume that a high GH also means a high KH, since most water sources have calcium carbonate as the main hardness component. But calcium sulfate in the water source will result in high total hardness, GH with low carbonate hardness, KH.

 

If peat socks did not reduce pH, then I think it is safe to assume you have a high KH. However 7.2 pH is not an issue, I think you are better off not adjusting pH at this point.

 

The plants display deficiencies, they never used to at 0 nitrate. I can add nutrients, I'd prefer trying seasol liquid seaweed before anything else - because I have some. I will also get some water changed out over time (I hate big changes in aquaponics) to remove hardness in this manner.

 

Liquid seaweed is great for micronutrients, if that is indeed the problem. Can you give an explanation of the symptoms. Include color, location (old or new growth, interveinal, stem, etc.), and pattern (blotchy, faded, sharply defined, round or mosaic). Also include plant species and describe fruit and flower deformities as well. I still have a sneaking suspicion that you are experiencing iron deficiency due to calcium excess, but this is just a guess based on your reported hardness readings. Adding kelp may help, but if you measured 500ppm GH, then this is the problem, and partial water changes will fix it.

 

Plants in hydroponics rapidly take up nitrate unless it is present in excess. While you may have had enough present to maintain adequate growth, the fish can handle higher loads, and the plants would definitely appreciate more nitrogen availability as well. Try to maintain between 10-50 ppm nitrate, 0 nitrite, and 0-5 ammonium (0 preferred).

 

The vinegar:medium test revealed a very high population of worms. Oligochaetes, but small, up to 30 mm. Approx 1 per piece of lava rock.

 

As long as you have correctly identified them, they are not a problem and are typical of aquaponic systems in need of cleaning. I recommend pulling a plant that looks like it may not make it, or is close to harvest, and carefully examine the roots. Make sure that there are no hydrogen sulfide smells, and that the roots do not appear slimy. They will likely not be particularly bright white as you would find in hydroponics, but a slight brown staining is fine. There should not be any slimy or foul smelling material in the roots or the medium. I have never used EM (essential micro-organisms?), and do not believe it to be necessary, but some people swear by it. I usually take a minimalist approach when it comes to additions to the nutrient solution.

 

I see this working, obviously, but question the increasing complexity as it adds to labour and set up costs while providing the problem of solids to be dealt with. Aquaponics has fantastic potential, don't get me wrong here, I just think it needs simplifying. Returning wastes to the food chain appeals to me, but practically, can closed aquaponic systems be sustained in this manner?

 

What do you think of my concept of skipping all the fancy equipment and running a straight aquaculture facilty (with biological filters) that pumps its wastes mixed with water changes directly to an outdoor garden project.

 

This is precisely the reason why I changed my mind at the last minute. Aquaponics relies on artficially high stocking rates of fish in order to maintain appropriate nutrient levels for the plants. Unless you are severely space limited, or are just doing a small hobby aquaponics set-up because of its novelty, I think you are better off with conventional pond aquaculture and organic soil gardening. My biggest problem was with the stock fish. Tilapia can not survive winters in my area, and they readily overpopulate unless you specifically cross breed to make all male hybrids or physically sex and discard the females.

 

I now have a half acre stock pond with catfish and bass, and I used to periodically pump water up to water the garden from the pond. A few times during the spring and fall, I made lettuce rafts that floated directly on the pond. Truth be told, I have now entirely separated the two systems (fish and plants) through laziness and indifference. The fish largely take care of themselves, and I get the majority of nitrogen needs from other sources for my garden.

 

Your system is larger than what I would consider to be a hobby system, and I would assume you are not looking forward to cleaning out your beds. Hopefully you have three beds of two square meters each. If this is the case, then you can easily get away with cleaning one out at a time. If it is all one big bed, then you will have to remove the plants and place a small amount of medium into a rigged up biofilter to keep effluent conversion continuous while you clean out the media. Monitor nitrate levels and do partial water changes to maintain water quality until your bed is clean and biologically active again.

 

Aquaponics would be great on the moon, or in the city, but in places were you have the space available, I would agree that it is overly complicated.

 

I now work at a nursery that uses a dammed stream to catch rainwater for its operations (approximately 200 acres and hundreds of thousands of potted trees). They also use small catch ponds to catch irrigation overflow and pump irrigation water out of these ponds. The irrigation ponds are stocked every spring with tilapia and are aerated spring through fall to combat algae. Algae, not fish waste, is the primary concern on clogging pumps. Since incorporating water agitation and tilapia, there hasn't been any pump problems that can be attributed to water quality. Water flows from 10 inch mains all the way down to 1.5 inch distribution pipes then into standard irrigation "spaghetti line" (1/4 inch inside diameter) to the emitters placed in each pot. They also use standard sprayers for smaller seedlings. I have never seen clogging problems for as long as I have been working there.

[Getting A Life]

Absolute gold Mr Jones.

 

I have the system split into 6, so if cleaning a bed or two out will help I can do that. Do you know the frequency of cleaning typically used in experimental ebb and flow designs at Virgin Islands?

 

Now - if there are sulfides (easy to detect I have a big nose) and I decide to clean up some beds - how do I clean them? Hose? H2O2? Sunlight?

 

I have some leftover hydroton, enough to fill a bed (90% of the medium is lava rock) so I could leave the medium to be cleaned for some time to 'process' if neccessary.

 

I'm glad you're an honest enthusiast, I grew tired of the evangelicals fairly quickly as I could never get a straight answer if it included anything detrimental to the 'ecological saviour' that was to be aquaponics.

 

What I LOVE about aquaponics is the ridiculously low maintenance for aquariums. And the breeding. Fish think aquaponics is all flowers and chocolates, subdued lighting and Barry White playing, you know...

 

What I never understood, till now, is that the clean up crew of worms etc in the beds, do not keep up as well as one might hope. I think my practise of leaving the root mass for the worms has something to do with the excess buildup in the beds.

 

I did add a sump a while back, under a bed, to see how much waste was making it out of the ebb and flow beds and to grow duckweed in.

 

What grows in the sump is lots of filamentous green algae that coats the duckweed. Siltation increases about 1 cm every 6 months. I remove excess and put it in the compost. The algae signifies high phosphates?

 

Sulphurous smells - first encountered a few weeks ago a bed clogged with roots at the drain as I pulled them out a good whiff of sulfur. Figured the blockage was the problem though. Will be in there sniffing round today, and getting some notes on plant appearances for you.

 

I really appreciate the time you're taken with me over this. Thank you.

[JMJones0424]

Do you know the frequency of cleaning typically used in experimental ebb and flow designs at Virgin Islands?

 

UVI doesn't use E&F, or at least they didn't when I went there. They use DWC with bio-filters removed from the plants. They also have the benefit of being in a relatively stable tropical environment, and grow only lettuce, so their needs are different than ours. They use settling tanks similar to septic systems to remove solid wastes and clean these out daily (but their system is MASSIVE). I have yet to see a long term E&F aquaponics set-up that does not require extensive periodic clean-out.

 

What I never understood, till now, is that the clean up crew of worms etc in the beds, do not keep up as well as one might hope. I think my practise of leaving the root mass for the worms has something to do with the excess buildup in the beds.

 

Absolutely agree. In my garden, I never remove root balls, as they help to provide structure and organic matter to the soil. However, your E&F beds have many orders of magnitude less surface area than an equivalent volume of soil, and leaving root mass in place is not a good idea.

 

Now - if there are sulfides (easy to detect I have a big nose) and I decide to clean up some beds - how do I clean them? Hose? H2O2? Sunlight?

 

Use a little experimentation. If the organic matter is stubbornly fixed onto the lava rocks, then you may require high pressure water to blast it off. Try thoroughly drying the rocks first, to aid in removal. I used an old water trough with one end slightly elevated and drilled drainage holes in the lower end, then laid a few inches of rock in the bottom and sprayed and churned until I got the majority of the organic matter off, then moved the rocks up to the high end and rinsed. It isn't a quick process, but if you do one bed a month or so, you should be able to keep ahead of the organic matter buildup. I used to use a weak bleach solution to sterilize the lava rocks after washing, as it is cheaper than hydrogen peroxide, but I gave up on it after a while, as it seems kinda silly to sterilize something that must be innoculated with bacteria to work correctly. The only thing I did notice was that in areas where sufficient build-up had occured to cause anaerobic zones, the lava rocks were typically stained black. I removed these and used them as inorganic mulch around annual beds. This may have been unnecessary, but I didn't like the fact that I couldn't get the black stuff out, and didn't know what it was.

 

I did add a sump a while back, under a bed, to see how much waste was making it out of the ebb and flow beds and to grow duckweed in.

I never did this myself, because i was growing fish for food, and didn't want to risk infectious diseases, but I have seen a system that incorporated a sump like you describe in-between the fish tank and the plant beds. Freshwater shrimp, snails, and many other water-dwelling "detritus feeders" could be stocked here to help process the waste.

 

...The algae signifies high phosphates?

 

Typically, from a planted aquarium approach, yes. However, realistically, you are not growing aquatic plants. And especially if you are growing flowering plants, if you have enough phosphorous in the system for the plants, then you will have more than enough for algae. The best way to limit algae in aquaponics is to limit sunlight penetration into the water.

 

What I LOVE about aquaponics is the ridiculously low maintenance for aquariums. And the breeding. Fish think aquaponics is all flowers and chocolates, subdued lighting and Barry White playing, you know...

 

That's an excellent way of putting it. It's funny, I got into aquariums AFTER giving up on aquaponics. The fish were always just a means to an end and a supplemental protein source for me. If you are in it for the fish, may I suggest you look into Diana Walstad's approach to natural, low-tech planted aquariums. She has an excellent book that served as a primer for my introduction to nutrient cycling and natural water chemistry in aquariums, Ecology of the Planted Aquarium http://www.amazon.com/Ecology-Planted-Aquarium-Practical-Scientific/dp/0967377315/ref=sr_1_1/184-2383580-6599047?ie=UTF8&s=books&qid=1257538131&sr=1-1

 

I'm glad you're an honest enthusiast, I grew tired of the evangelicals fairly quickly as I could never get a straight answer if it included anything detrimental to the 'ecological saviour' that was to be aquaponics... I really appreciate the time you're taken with me over this. Thank you.

 

It is annoying isn't it. The world would be a lot better off if ideas were allowed to stand on their own merit. I have yet to find a magic bullet for anything. I am however continuously fascinated with all aspects of the complexity and inter-dependency of nature. And I am always happy to share what I have observed and learn from other's observations.

[Getting A Life]

OK. The root systems are clean and healthy. Albeit, diminished. I pulled a plant from each bed. No sulfurous smells.

 

It is definately an iron deficiency. "interveinal chlorosis occuring first on younger leaves. In severe cases, younger leaves become white with necrotic lesions."

 

Very keen on your advice with regards to iron supplementation.

[Getting A Life]

So much good information you have given me, my mind has been mulling over things all day. If 1/4 inch diameter does not clog with aquaponic water the set up for a pond/garden system would be simple indeed.

 

Pond design can get pretty elaborate but I find lining a hole in the ground works for me. ;)Of course using this 'simplistic' approach I had a half a pond after the first heavy rains lifted it.

 

Now I find lining a hole in the ground, with drainage, works for me. :)

 

Then a timer and pump pumps water from the pond to beds, and gravity brings it back.

 

If I were to skip the beds altogether, and irrigate raised beds around the pond with the timer and a much smaller pump... Daily water exchange at a rate suited to the stocking density. I'd have free nutrients for my garden, no problems having to water my garden anymore, Then add a reservoir with pipe to the pond, (simple sealed barrel stored anyplace above pond with pipe leading to pond that draws air and lets water flow out when water in pond is below it) I could have a simple set up indeed.

 

Barrel, plumbing, pond, pump, timer, irrigation, patch of dirt.

 

Add an automatic fish feeder and you could go on holiday and come home to a fresh BBQ.

 

I love the concept of empowering people to grow their own food in small spaces with tight budgets. Aquaculture can be expensive and maintenance heavy, I think the aquaponic concept untenable at this stage on a large scale (so many businesses are no more) but the idea of growing fish and vegetables in harmony still appeals.

 

The production of protein in one's own backyard is very appealing. The use of omnivorous species has a lot of promise. Systems may start to utilise wastes growing algae, duckweed and azolla for food, with solids processed by black soldier flies whose larvae will self disinfect then crawl out and drop into any waiting receptacle (including your pond).

 

There are other crops that may benefit greatly from aquaponics. Watercress, taro, rice? I live in a small part of the world I'm sure there must be many more freshwater aquatic/terrestrial plants of economic significance.

 

Increasing complexity of the ecosystem will eventually lead to aquaponic systems that do not require cleaning (ie: multiple aquatic species and terrestrial species of plants, shrimp and snails, bottom feeders, etc) but this is not tenable for anything but a hobby (yet).

 

So, removing the solids seems the easiest option, and for me, this requires using them to advantage, making an income stream out of crap if you will. There are a few options.

 

What is your opinion of where to go with a garden/pond system.

 

1. Pump to a sump to seperate solids first before the garden.

 

2. Grind solids up in the pump and put it straight on the dirt.

 

Not going to change my system, but after I get a place of my own... I want at least 10000 litre pond to play with, and as little maintenance as possible.

[JMJones0424]

What is your opinion of where to go with a garden/pond system.

 

1. Pump to a sump to seperate solids first before the garden.

 

2. Grind solids up in the pump and put it straight on the dirt.

 

If your garden is soil, and not lava rock, then there's no need to remove the solid waste. The pump does a great job of "chopping" up the fish waste, and as long as you keep filamentous algae out of the pump, I don't think you'll have any problems. Unless of course you want a bog type ecosystem, then you could draw waste water from the bottom of the pond, pump it through a shallow area heavily planted with marginal aquatic plants and various critters, and then the now filtered water drains back into the pond. Grab a quarter of the water once a week or as needed to keep nitrate levels in check, and to provide extra fertilizer for your soil garden. There's many different ways you could go, and it sounds like you know enough of the basics to make it work. As long as you don't overstock the fish pond, there isn't really a lot that can go wrong. Try Robyn's fishpond site for general hobby level information about developing diverse backyard ponds.

 

Glad I could be of help!

[christopher99]

I have gotten a lot of help from this article related to hydroponic tips and ideas.

 

I thought I would share this. Not sure how long this link helpful for you.

 

http://www.rosebudmag.com/hydroponic-tips-ideas