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shakaho

Mini Aquaponics System

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After 14 years of failure trying to grow vegetables in FL sand, I dreamed of an  aquaponics system.  A 1000 gallon pond could fit in the failed garden spot and could feed `a huge garden of grow beds.  However before I made a big investment, I wanted to build a tiny model system to make my mistakes on.  

 

So I looked at my 50 gallon Rubbermaid stock, the same one you saw here and here and started planning.  I had a filter already running in the pond,  and decided on a water flow  from pond via a retrofit bottom drain to a radial flow filter in a 5 gallon bucket, to another 5 gallon bucket containing the pump, through pvc pipe to the biofilter,  to the grow bed, and back to the pond.  So first I just set containers in place  to see if everything fit.

 

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I need the tops of the fish tank and the buckets (radial flow filter and pump)  the same height, so I elevated the pond on half-high concrete blocks and the buckets on round stepping "stones."   The front bucket becomes the radial flow filter, the back the pump bucket.  The future grow bed, an IKEA storage box, should be at the right height on concrete blocks on end.  The filter is busy elsewhere.

 

First I had to make my retrofit bottom drain.  This functions as a continuously-running bottom siphon, taking water from the bottom of the pond to the radial flow filter where some of the solids will settle out.  The builder of  this DIY retrofit bottom filter  explains the process very well.  The "bowl" over the intake of the bottom drain assures that the water coming in comes from the bottom of the pond.  

 

I found a microwave plate cover that looked like it would make a nice bowl.  It has a steam hole in the top that I enlarged to allow a 1" pipe to go through.  Ideally, the hole would be in the middle, but I preferred to live with an off-center hole rather than closing that hole and making another.  My legs were simpler.  I just cut 1" pieces of pipe and sawed a slit halfway through it, and pushed them onto the "bowl"

 

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To put a pipe through the top of the bowl, I used this and this.  I made a hole just big enough for the male adapter to go through, then screwed on the female adapter on the other side.  You find these conduit fittings in the electrical department, not in plumbing.  The white plumbing fittings do not screw together all the way, the conduit fittings do.

 

Gradual curves provide less fiction than sharp turns, so I used two "45 degree" elbows instead of a single 90 degree elbow.  The pipe will go through a uniseal in the wall of the tank.

 

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I put a ball valve on the pipe outside the tank so that I could shut off the flow to clean the buckets.

 

I use a radial flow filter, a type of settling chamber, for  mechanical filtration. 

 

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The radial flow filter sediments suspended particles by accentuating the downward force of gravity.  The water and its suspended particles go up through the pipe to the top of the water, then "bounce" off the air-water interface.  The outer pipe focuses their direction -- down.  The momentum of the bounce adds to the force of gravity, speeding their fall.   As a result, the sedimenting particles tend to stick to the bottom.  

 

(To be continued)

Edited by shakaho

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Your posts always delight and fascinate me :hi5

Thanks for all you contribute :D

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Looking forward to more...

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Thank you, Flipper and Lisa.

 

Continuing...

 

The next step -- the radial flow filter -- appeared  an easy build.  Connecting the outflow pipe to the filter, however, presented challenges.  Ideally, the pipe from the tank enters the filter near the bottom.  However the height of the retrofit  bottom drain forced the outlet to near the top of  the tank.   This meant instead of the one 90o angle in the diagram, I needed 3 such angles.  Every angle increases friction and slows flow.  I had two choices:

 

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Initially, I chose the first.

 

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For some reason that I have forgotten, I later changed to the second.  

 

I also needed a pipe to the pump bucket, and the holes had to be on the same level.

 

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I can tell you in hindsight, that this connecting pipe should be lower for optimal performance, but I did eventually get this to work.

 

Between the two buckets I used a union, which allowed me to easily separate the buckets for cleaning. 

 

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The pump, which came from Harbor Freight sits in the pump bucket.  I used pvc pipe rather than hose to take the water from the pump bucket to the biofilter, a move that greatly increases the flow rate.

 

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The biofilter is one I had working before.  I constructed it like the one here, but used the pretty flowerpot instead of a bucket.

 

(To be continued)

 

 

 

 

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:thud I'm exhausted just thinking about all of this. You amaze me. :o

I think it'd be easier to move to a state with a more garden friendly soil/climate. :rofl3

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Lisa, go back and read the first paragraph I wrote to understand my motivation.   :lol2

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:lol

 

You still amaze me.  :hi5

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Wow Sharon.  This is brilliant!  I wonder if I can convince Hubby this would be a good idea?  We have sand here rather than sandy soil.... not fun to try to grow stuff in!

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Aquaponics is big down under.  Visit this site.

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Aquaponics is big down under.  Visit this site.

 

That is an amazing site Sharon.  Just a couple of questions....

 

  • How do you work out how much grow bed a pond or so many fish can sustain? 

 

  • Can you keep more fish with this kind of system, considering the greater filtration and water volume in the plantbeds, than you could in a normal pond situation?  What do you consider the figures would be like so many fish/gal? or would these vary too greatly to approximate?

I hope that makes sense... if you need clarification, pls don't hesitate to ask... my brain has knocked off for the night!

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This article discusses your first question, and this article discusses both.  Do read this, since it deals with small systems.  The rule of thumb I'm getting says a grow bed volume one to two times that of the fish tank works well.  Grow beds have less depth than fish tanks, so even when volumes are equal you have a lot of grow bed area.

 

Aquaponics systems using tilapia may stock at a level of 1/2 pound of fish per gallon of water.  I think they refer to fish tank water rather than system water.  While tilapia don't mind poor water conditions,  that stocking level requires one to have things like an emergency generator in case the electrical failure, since the fish depend on filtration for survival.  

 

recommends one pound of fish per 8-10 gallons of tank water.  He also says that, with young fish, you should follow that rule using their adult size, just as we do in Kokos.   So if a large goldfish weighs about a pound, at this stocking level, if a pump goes out,  the fish will do fine for quite a while while. (But they appreciate getting the water flow restored.)  You might think his recommendation is heavy stocking compared to our recommendations, but consider the whole system.  For ponds, we recommend a filter that contains 1/10 the volume of the water in the pond.  The aquaponics system uses filters that are 1 to 2 times the volume of the fish tank.  So the system provides something on the order of 15-30 gallons per fish, plus superior filtration.

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This article discusses your first question, and this article discusses both.  Do read this, since it deals with small systems.  The rule of thumb I'm getting says a grow bed volume one to two times that of the fish tank works well.  Grow beds have less depth than fish tanks, so even when volumes are equal you have a lot of grow bed area.

 

Aquaponics systems using tilapia may stock at a level of 1/2 pound of fish per gallon of water.  I think they refer to fish tank water rather than system water.  While tilapia don't mind poor water conditions,  that stocking level requires one to have things like an emergency generator in case the electrical failure, since the fish depend on filtration for survival.  

 

recommends one pound of fish per 8-10 gallons of tank water.  He also says that, with young fish, you should follow that rule using their adult size, just as we do in Kokos.   So if a large goldfish weighs about a pound, at this stocking level, if a pump goes out,  the fish will do fine for quite a while while. (But they appreciate getting the water flow restored.)  You might think his recommendation is heavy stocking compared to our recommendations, but consider the whole system.  For ponds, we recommend a filter that contains 1/10 the volume of the water in the pond.  The aquaponics system uses filters that are 1 to 2 times the volume of the fish tank.  So the system provides something on the order of 15-30 gallons per fish, plus superior filtration.

 

Thanks Sharon for the information.  I will definitely have a read.  What a great system... if it sustains more fish in a tank/pond, and at the same time you get loads of vegies!  I win (more fish), Hubby wins(great fertiliser, not having to spend time watering)!  :teehee

 

I just had a another couple of questions.  The vegies would have to be organic wouldn't they, otherwise pesticides in the water would not be good for the fish... and its the way I would prefer it anyway.  I have seen some natural pesticide sprays using garlic (which I know would be fine), but some I have seen also have chilli in them.  How would these go?  I am presuming that they are really not a good idea in this system.  What else would you use for pesticides? 

 

Also, we would be growing the kind of crops I can eat (I have severe diet restrictions), but are expensive to purchase like shallots/leaks, swedes, brussel sprouts, chokos (chayote), and cherry tomatoes for hubby.  How would the root crops like swedes, and the shallots/leaks go in this type of growing medium?  I know that most root crops are usually grown in a fine soil.  This might sound like a silly question, but could I add a 'pocket' of fine soil somehow and wick water through the system, again somehow, similar to how I wick water my African violets?

 

Sorry about all the questions... I was wondering if I should create another thread and post them there instead of here.  I'm not sure if I am hijacking your thread or not... If I am I am so sorry... just let me know, and ill do accordingly.

 

Thanks again for all your assistance.  This is just blowing my mind how great this is!

Edited by Ree

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Search root crops in Backyard Aquaponics.   Leeks and other members of the onion family  appear to be very easy to grow, but people seem to grow almost anything in their aquaponics systems. Greens grow far better in ponics systems than in soil.  Tomatoes go crazy.  

 

I started gardening organically as a teenager in the late 1950s.  At that time experts declared organic gardening impossible and its practitioners crackpots.  Unlike today, when the first question newcomers ask about organic gardening is , "Where do you get organic fertilizers and organic pesticides?"  we fed the soil and let the soil feed the plants, and encouraged development of an ecosystem that restored predator control of pests.    The only pesticides I ever used were oil/soap and BT.  I composted kitchen and yard wastes in a bin, and mulched deeply with leaves and grass clippings. It worked fine.  Then we came to FL.  

 

Peninsular FL is just a sandbar.  We typically get almost daily heavy rains through the summer which wash nutrients out of the topsoil.  One can garden organically here, but it requires incredible amounts of labor, or purchasing lots of expensive organic fertilizers and soil supplements (and lots of labor).  During the winter, the rains go away almost completely.  We have temperatures appropriate for growing temperate crops, but must irrigate, which we can do legally once a week.  So you can see why many people have taken up hydroponics and aquaponics.

 

A lot of plant pests inhabit the soil, so you have less problems when you garden without soil.

 

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Very interesting!  I can't wait to see how it turns out!

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Search root crops in Backyard Aquaponics.   Leeks and other members of the onion family  appear to be very easy to grow, but people seem to grow almost anything in their aquaponics systems. Greens grow far better in ponics systems than in soil.  Tomatoes go crazy.  

 

I started gardening organically as a teenager in the late 1950s.  At that time experts declared organic gardening impossible and its practitioners crackpots.  Unlike today, when the first question newcomers ask about organic gardening is , "Where do you get organic fertilizers and organic pesticides?"  we fed the soil and let the soil feed the plants, and encouraged development of an ecosystem that restored predator control of pests.    The only pesticides I ever used were oil/soap and BT.  I composted kitchen and yard wastes in a bin, and mulched deeply with leaves and grass clippings. It worked fine.  Then we came to FL.  

 

Peninsular FL is just a sandbar.  We typically get almost daily heavy rains through the summer which wash nutrients out of the topsoil.  One can garden organically here, but it requires incredible amounts of labor, or purchasing lots of expensive organic fertilizers and soil supplements (and lots of labor).  During the winter, the rains go away almost completely.  We have temperatures appropriate for growing temperate crops, but must irrigate, which we can do legally once a week.  So you can see why many people have taken up hydroponics and aquaponics.

 

A lot of plant pests inhabit the soil, so you have less problems when you garden without soil.

 

So basically the idea is the same as keeping goldfish... to keep the system/plant as healthy as possible, thereby the system/plant will be less likely to succumb to disease? 

 

I looked up the website, but they had nothing matching root crops.  They did however have a growing chart that mentions root crops.  I will have to do some more research into this I think.

 

You just reminded me my great grandmother I guess could be called an organic gardener.  Every day she would go out into the garden armed with a sharp pair of scissors, and cut any of the grubs/pests in half.  LOL... Id forgotten about that till just now. 

 

Thanks again Sharon.  Your always answer my questions!  I LOVE that!  Thankyou so much!  :hug

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Sorry.  Go to Backyard Aquaponics, then "Aquaponics Forum" (second link at the very top of the page) and search there for root crops.  I have no idea why a full site search doesn't cover the forum.

 

You don't have to cut any pests in half, just feed them to the fishies. :)

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Sorry.  Go to Backyard Aquaponics, then "Aquaponics Forum" (second link at the very top of the page) and search there for root crops.  I have no idea why a full site search doesn't cover the forum.

 

You don't have to cut any pests in half, just feed them to the fishies. :)

 

Oh Sharon, If only I could 'like' this three times!  I nearly lost my mouthful of water!  PERFECT solution!  :happydance

 

I wasn't really relishing the idea going out with a pair of scissors and cutting things in half!  I would feel sorry for them and turn them into pets first.... I had a pet caterpillar when I was about 3yrs old.  His name was Cassius.  I had him for a full 24hours.  Then I took him for a walk and put him on a bush so he could have some dinner, went back to get him a couple of hours later, and would you believe it? he was gone!  I spent days wondering around the backyard calling 'Cassius.... Caaaaaaaaaaaassius', but he never answered.  Strange little kid wasn't I? :doh11:

 

Fish feeding a much better idea!  Thankyou

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OK.  Back to the mini aquaponics system.  The biofilter empties into the grow bed.  Concrete blocks standing on end bear the weight of the grow bed, but I need a platform to provide uniform support.   I started by making a frame of 1x2 pvc lumber.

 

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Then I cut a piece of plywood to fit on top of it and wrapped it with plastic.

 

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Then I topped this with plastic paneling.

 

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After a coat of paint, I put it on the cement blocks and set the grow bed on it.

 

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We want the water to go up from the bottom of the grow bed, so I run a pipe from the biofilter outlet to the bottom of the grow bed, put a tee fitting on the end of the pipe and put "holey pipes" into the tee, so the water spreads across the length of the grow bed.

 

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Then the water will percolate up through the grow medium and exit through a stand pipe that ends an inch or two below the top of the media.  One has to put some type of porous barrier around the stand pipe to keep the grow medium out.  Most people use a holey pipe.

 

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This did not work.  The holey pipe works fine when the stand pipe drains from the bottom of the grow bed.  However space problems led me to have the water exit through the side.   I couldn't find a good way of keeping the grow medium from slipping under the holey pipe and out the stand pipe.

 

So I went back to one of my favorite materials and made a box around the stand pipe out of Matala. 

 

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This worked.

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Now to summarize the water path.

 

Water from the bottom of the fish tank basically siphons from the retrofit bottom drain into the radial flow filter.

 

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The water is entering the radial flow filter from the pipe at the lower left of the picture and exits to the pump bucket through the pipe at the upper left.  Ignore the other pipe.  That's just  there to close a hole in the wrong place.

 

You can see in this picture that I changed to having the pipe come straight through the side of the bucket, then turn toward the bottom, make a u-turn and come out near the top of the water.  This makes particles bounce off the top of the water and speed to the bottom of the bucket where they tend to stick.  The larger pipe serves to "focus" the water flow.  You see the dirty ring in the bottom of the bucket.  In a couple of days the bottom will be all black.   Also, the water bubbling at the surface is picking up air.

 

Her the water flows into the pump bucket.

 

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Note the bubbles and agitation at the surface of the water.  More aeration.

 

When the water arrives at the filter, it makes a right turn toward the bottom.  The open top of the tee-fitting provides air that get incorporated into the swirling water.

 

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I probably should have used a video so you could really see the turbulence of the water. You can see all the bubbles coming up from the bottom of the filter.  If they were coming through medium, the bubbles would break into smaller ones as they bounced off media.  Likewise the water flowing into the outlet pipe swirls as it goes in incorporating air.

 

I thought I had a picture of the water swirling in the tee that steers it to the bottom of the grow bed, but I can't find it.  On the right of the picture below you can see the bubbles coming out of the holey pipe in the grow bed.

 

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I point out all of these points of aeration because aquaponics doesn't work without aerated water (or a fill and drain system).  The roots of terrestrial plants die without oxygen.  Aquatic plants and marginals pump oxygen from the leaves to the roots so the root cells do not need to get their oxygen from the outside.  People often use airstones or venturis to add extra air to their water.  In this system, with a shallow grow bed and a shallow fish tank, it seemed to me that I needed no additional aeration.

 

 

 

 

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With all of the containers and plumbing in place, I started bring the system to life.

 

I used hydroton  grow medium, made of expanded clay pellets.  I prefer growstones, made of recycled glass, but couldn't find them locally.  You can get either of these on line.

 

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I started off with a couple of tomato plants and some strawberries.  Then I threw in some seeds to se what would grow.

 

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The plants are growing rapidly.

 

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Notice the yellowing of some strawberry leaves.  It looks like a nutritional deficiency -- not unusual in a new system.

 

 

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Sharon, the growth rates are amazing.... I am really loving this system. 

 

Do you have to dose with aquatic fertiliser for a few months till you get past the nutrient deficiency stage? 

 

Thankyou so much for sharing your build!  :bighug

Edited by Ree

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:lol

 

You still amaze me.   :hi5

:bingo:

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Ree, I read advice to add some diluted hydroponic solution to a new system to get the plants started before you add fish if you have a cycled filter, or while you are cycling if you are cycling with just a few fish.  Unfortunately, I forgot to bookmark the site and can't remember how much to dilute it.  By doing this, you get some big plants ready to gobble up the nutrients produced by the fish as soon as these appear.

 

Aquaponics systems typically require iron.  Fish food contains little iron, so fish waste contains little iron.  Most forms of iron do not dissolve in water with neutral or basic pH.  

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It turned out that I needed to add iron, magnesium, and potassium to my system. This happens regularly with new systems.  In spite of looking sickly, my tomatoes grew and fruited.

 

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I had to put up some support for the tomatoes, but didn't take a picture of these when the fence was loaded in the fall.  But here it is in spring.

 

 

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A month and a half later.

 

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I'm eating tomatoes from this every day.  I put the bok choy in a little late and it bolted, but the chard provides me with a lot of nice greens. I got several kohlrabis, but these are winter vegetables  here and pretty much done until fall.

 

Would you like to see the fishies?  I put most of the red/orange metallic fantails in here.  Two or three of them are nymphs, but you can't see their tails.

 

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You think I'm overstocked with 8 fish in a 50 gallon tank?  Well this system has a water volume of 90 gallons.  Just a few years ago, this board recommended 20 gallons for the first fish and 10 gallons for each additional fish.  (Most sites still recommend this for goldfish.)  That would make a 90 gallon aquarium big enough for eight fish.  

 

While aquaponics systems with tilapia -- which tolerate horrible water conditions -- may allot only 3-5 gallons per fish, the fish-friendly stocking level allots 10 gallons per pound of mature fish, even for baby fish.  In some of the big commercial systems with  state-of-the-art filtration systems, the water that comes back to the fish tank is actually cleaner than the tap water.  

 

When I put these fish in the tank in March, most of them were small enough that I worried they would go out the drain.  Look at the clarity of the water.  Aquaponics filtration produces really good water.

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This is a wonderful aquaponics system and something I would love to have here, even though I have a huge yard and greenhouse with lots of good ground for growing things. But...here it is April 5 and I still have a few feet of snow on the ground (sad but true). I would love to see where you are with the system today and hear how you supplemented your water to fix the nutrient problems.

I would put this in my house, if I had the space, for growing winter greens and what not. I'm excited to get my little system going.

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