Backyard Aquaponics
A place to discuss aquaponics

I have kept aquariums for 20 years and grown hydroponics for 3...its time to try aquaponics. I am planning an outdoor system based on a 125 gallon aquarium using a 50 gallon barrel for a sump/refugia and planning to grow cherry tomatoes, cucumbers and hopefully dwarf peppers. I have not decided between channel catfish and yellow perch for the fish. I will raise killifish, guppies (in the sump) and red wigglers for feeders and rely on homemade fish food (customized beef heart / liver/ cheap fish / veggie blend). The spot is on the west side of my house and gets constant afternoon sun.

I am curious about a few major elements of the system.

1) I am unsure about water flow rates and filtration. I am planning on using a 500 or 600 or 700 gph pump running through a spray-bar onto 5-10 gallons of filter media (pea gravel, coconut basket material and poly pillow fill) into the sump and then past 18 square feet (6x3) of planting space (24 plants-3 rows: cherry toms hanging off the front, peppers that stands upright and cucumbers that climb up the wall behind the system).

2) I want to use a continuous flood method. I am planning on using 1 gallon smart pots (cloth pots about 8 inches deep) filled with coco coir and keep them constantly flooded an inch or so deep (however deep is needed to wick them wet to within an inch of the top). In the top inch of the wicking zone I will mix compost/castings/kelp meal. Then top the pots with a disposable plastic plate to keep the rain from washing the nutrients from the top layer into the tank.

-Is the flow rate enough?
-Is the filter media enough?
-Is the compost/wicking idea just a complicated way to kill my fish (a company called grow power in Wisconsin does it...I bet they have more experience than me). Is their an easier way to feed them?
-How many fish?
-Will these crops tolerate the constant moisture in the bottom of the pots?
-The sumps not really a sump just extra water and a place to raise feeders but I could add an airlift under gravel filter pretty easy....is it needed?

Thanks in advance.

79 views and NO THOUGHTS. Anyone

From a Noob...

-Is the flow rate enough? You'll need to turn over the volume of your tank at least once per hour 500 - 700gph is sufficient.

-Is the filter media enough? Pea gravel, coconut basket material and poly pillow fill, sounds O.k

-Is the compost/wicking idea just a complicated way to kill my fish (a company called grow power in Wisconsin does it...I bet they have more experience than me). Is their an easier way to feed them? There is other topics about wicking beds, check them out.

-How many fish? In a 125 gallon tank, maybe 10 fish, stocking depends on filtration capacity,
-Will these crops tolerate the constant moisture in the bottom of the pots? Yes..

-The sumps not really a sump just extra water and a place to raise feeders but I could add an airlift under gravel filter pretty easy....is it needed? The sump water should be clean enough to sent back to the fish tank (suppose to be), maybe some pics or diagrams would help.

From what I've read about wicking beds its generally not applied to AP accept for waste water...which is certainly an option (then I could add hydro nutrients if needed) but then the grow bed is not a filter.

My main concern is that the grow area will be wick based so I'm not sure I can count on it for bacterial filtration since wicking is fairly directional...(i.e. the water is not really exchanging very well). On top of this I am at 24 gallons of media so I have to reduce the stocking rate way down. I could put the pots on a bed of gravel but it would not increase the media volume very much. I'm not concerned with raising a ton of fish or veggies but I want it to work.

According to http://aquaponicsusa.wordpress.com/2011/02/07/ I could do 40 lbs (200 Yellow Perch at 200 gram max) if I had 20 cubic feet of hydroton bed. I've got 3.3...so 30 fish minus allowance for the minnows and a little more for error and a little more for the bad design = 10 ?

I think I'll go back to the drawing board and try and get it up to 50. I've got some old 4x4 flood trays that probably need worked into the system.

If you just want something that works, then perhaps you need to go for a tried and tested method rather than something that's unusual and facts and figures aren't so well established.

It's hard to give answers on a system that's quite different to what most people have. I think if you want to follow down the path your heading, you really need to look at having a small recirc aquaculture set up with biofilter and solids removal, then a small offset of that being your plant side.

I don't really like the figures you linked to, I would stay away from there... 500L of media allowing 40 lb of fish or 200 x 200g fish... Also on feeding "supporting up to 4 feedings every three hours" Thats got to be an error surely...

Thanks for the help.

"In a 125 gallon tank, maybe 10 fish, stocking depends on filtration capacity" Is this number so low because I have such a small bed or maybe you were thinking bigger fish?

""I don't really like the figures you linked to" I get pretty similar results using the calculator created bu University of Virginia... http://www.aquaponic.com.au/backyard.htm ... and they also mention/recommend the separate biofilter and solids removal for systems like mine. Is that different from the filter I put above the sump (it was a 10 gallon shop vac container). The calculator says 125 gallons 20 lb fish and 25 cubic feet grow bed (for leafy greens and 14 for fruiting plants) but it also says 4 gallons of biofilter could replace the bed (if solids are removed or a giant mineralization bed is used). Based on the calculator results, It looks to me like the large bed volume is needed for mineralization of solids not ammonia conversion and that the extra filter I added should get things back in line (allow a bunch more fish).

Is anyone familiar with this calculator?

The problem I am seeing is that I could have a tiny tank and giant grow bed and raise the same number of fish I will get with a big tank and small grow bed. I've already got 1000 square feet of garden so the veggies are not a priority. I'd rather figure out alternative filtration and get the fish numbers up.

PS I got the tank and barrel free.

That's not the university of Virginia. Generally if you ask 10 different people you might expect to get 8 different answers.

You're also mixing different things, you're using a calculator and peoples information that are focused on media based systems where water is flowing through the media constantly or periodically, then trying to transpose this information over a system running in a totally different way with wicking pots.

I'd recommend you increase your biofilter size and run it as a recirculating aquaculture system then you can stock a whole lot of fish, then do your water changes into your dirt garden or a small wicking pot system.

Whoops, it is the University of the Virgin Islands (even better) by Dr James Rakocy I was reading too fast. This is a page that explains the calculator... http://www.aquaponic.com.au/Aquaponic%2 ... nation.pdf ... It is NOT only for media based systems and has specific calculation for biofilter size and flow rate for non media systems. Although, the figure it gives seems very small (2 gallons for 10 lbs fish) and is based on solids removal in conjunction with deep water culture or NFT (without solids removal it calculates a mineralization bed that is generally very large 5.6 cubic foot for 10 lbs fish)

I agree with the 10 people 8 answer comment...in this case I think I'll trust the guy with the PhD from one of the most respected aquaponics organizations in the world. Although, I fear the pro's model assumes some experience so I'll error on the side of caution. AND, I bet if you ask 10 PhD experts you still get 3 or 4 answers. Do you think a lot of this is due to the solids removal (or not)?

I also like the idea of big biofilter and drain to wicking bed idea. Any guess as to how big the biofilter should be. I'm leaning towards 10 lbs fish (30 or so fingerlings and minnows to start). I've read Yellow Perch culture is a 10 week process that yields 100-150 gram fish (once again that's the pro's). I've got 18 weeks and will harvest at 200 grams or when I run out of summer.

Thanks again for the help.

PS. my 200 x 200 math was way off...I'm not great with grams. In theory it would have been 160 x 112 grams = 40 lbs.

(Edit: after more thoroughly reading the thread, i realise you have come to most of the conclusion below, but here some support)

You seem pretty set on two things. The wicking idea, and higher stocking densities.

My advice for the wicking idea (as with EarthBounds advice) would be 1) set up enough "normal" AP media filled grow beds or biofilters to support the stocking density you want. 2) then run the wicking beds as an add on.

Lots of people do this approach. They will start with a media filled growbed system then add different technologies to the chain, e.g. Nft, dwc, wicking beds, grow towers.

For the stocking densities see above. Also, whether you have enough biofiltration is always going to be a judgement call, and i personally would always go overboard on filtration:stock ratio until you know your system (as you have already said). Better safe then sorry.

"Is this number so low because I have such a small bed or maybe you were thinking bigger fish?"
This estimate of 10 was probably made without knowledge of your extra biofilter size.

"they also mention/recommend the separate biofilter and solids removal for systems like mine"
I think this is the key in your situation, knowing that the calculator incorporates biofilter calculations ties everything together. Obviously different biofilter technologies give different results. I can run an aquarium biofilter and seem to get the same level of filteration as 50lt of grow bed (just an observation, not science). If you dont want to run normal media filled "high" volume grow beds I would suggest going overboard with other biofilter technologies.

The advice of people on this forum is generally 3kg of grown out fish per 100kg of growbed media, you'll need to adjust for your extra biofiltration, but sorry.....I've got no answers on size.


P.S.
On the topic of trusting PhDs or their tools over a forum, remember a few points:
- here we get to read an actual account of your plans and responding to it directly, a calculator has no deduction skills
- Not judging uni of viriginia island, but PhDs are not everything (I should know):
+ I know lots of idiots with PhDs
+ I know some non-idiots with phds who at one time or another have spread miss information accidentally. Research is just that....research, information provided is not always the final/best methods we have
+ I know plenty of people smarter and more experienced than people in the same field with PhDs
- EarthBound could probably get a phd by publication in AP. He wrote "the book" in Australia in home aquaponics. Plus his profession is home AP.

Don't look at my comments as a flaming, the last part about phds is really just an "top end of the scale" example I wanted to make on the great PhD misconception. You clearly are well read and educated on what the calculator is capables of so take from it what you like. However, if people on this forum said they would run 200x200g fish with 500lt or media filled grow bed, most members would freak out.

Dr James Rakocy didn't write it, it's by Dr Wilson Lennard in Australia... Nothing to do with the Virgin Islands, though he has used some of their findings in the explanation.

3 kg per 100 kg is where I started but I have trouble with the weight of the media being relevant because of variability in weight and bacterial holding capacity between media (pea gravel vs hydroton vs perlite). Does anyone know what media this assumes (or how it relates to square feet or square meters)...it will cost a lot more to buy 100 kg of hydroton than to shovel gravel from the creek.

I agree about the PhD points and did not mean to offend anyone or imply they lack experience. As a noob on the forum I have no idea about anybodies history but I can be sure the guy with the PhD has actually worked with an AP setup (I'm sure you have all come across the BOOK SMART forum pro with NO experience). I also presume that a University derived calculator must be fairly accurate and if it was not it would not have stayed on the internet for years (if only because Dr Whoever would get sick of the hate mail). Not exactly scientific but thats why I came looking for extra help.

Correct its Dr Wilson Lennard in Australia, sorry to start any confusion. Anyone know of him or his work? The most interesting part is the idea that ratios should be between surface area of bed and feeding rate NOT stocking density and media weight/volume.

I'm NOT set on the wicking idea but I have a ton of free coco, a bunch of old smart pots, have had bad luck with ebb and flow coco (it needs a lot of time between floods which seems like a bad idea for a biofilter that needs to be dependable), and need to limit the grow area to the "lid" of the tank because of space constraints (and its not gonna support 100 kg of gravel). I AM set on growing a fruiting plant (tomatoes, cucumbers and/or peppers) and saw that GrowingPower has had good luck with a wicking coco and compost (worm castings I believe) system. If I can do it too than I don't really have to buy anything. So far I have spent $8 on PVC and poly fill...anyone can get it right if they spend the big bucks.

I don't need a 50 gallon sump to raise minnows, would it be effective to fill the bottom half of the barrel with gravel and drain through it like an "reverse" under gravel filter (in addition to a 10 gallon media biofilter and solids removal)?

I hate to sound like I'm trying to re invent the wheel...but their is a reason the wheel is no longer made from stone. And I am really just borrowing the idea.

Anyone know about the Growing Power project or if any of them are members here?

growing power in milwaukee is a "non-profit" - they have several income streams beside the fish and veggies - they sell compost, worm tea, and i believe they are now selling fish (by product) fertilizer
it's not really the "weight" of the media in the calc's but the "volume", and the calculater default value for surface area of the media is if you are using hydroton..
all of the practial experience on this message board, that has seen just about every variation you can think of and probably several you could not.. but the basic "stocking density" rule of thumb will help you avoid fish kills..and provide you with a good basic understanding of the concepts, so that when you do decide to go with a high volume of fish, you'll know what to look out for..
100 gallons of growbed volume for every 25lb of grown out size fish..a little over 30 yp if you grow them out to 12oz size

Try this thread viewtopic.php?f=1&t=12204

cheers

+1 Keith

I see no reason that the wicking option would not work. The main thing is the media will eventually require replacement while rocks would not. I wouldn't expect much filtration from the coco coir. On the other hand you might find that this wicking arangement works well for carrots and other root crops.