Backyard Aquaponics
A place to discuss aquaponics

So I've been farming for years and I'm finally getting a hoop house. I'd like to transition it to a continuous flow aquaponic setup as well. We'll likely be building an 18'x72' gothic hoop house, air insulated 6mil poly, and solid dual layer poly end walls. I plan on installing a climate battery and potentially a rocket mass heater to hopefully gain a couple zones (I'm zone 5b just outside Lafayette, CO and we get lots of sunshine) and extend my season. The greenhouse runs E-W with the pond on the north side and grow bed(s) on the south side and a small sitting area in the Southwest corner. I'm a total newbie to aquaponics but I've been doing a fair amount of reading and this seems like it would work but let me know if I'm off my rocker

Here's my initial thoughts on a layout:



Pond: ~4ft wide, 2.5-3ft deep and 55-60ft long pond so somewhere between 4100-5400 gallons. Add small trickling waterfall either with return water from the beds or a small additional solar powered pump. Planning on putting reflective backed insulation on the north wall to hopefully redirect extra sun and heat into the water during winter and shade it during the mid-late afternoon of summer. Use an airlift pump to pump water up to the beds. My wife and son won't eat the fish so I'm planning on raising koi. Beautiful, tolerate of temps and could hopefully potentially resell them.

Beds: Flow through two gravel beds that filter before flowing into the raft beds. What is the preferred method to flow from one bed to the next? Especially to get the cleanest water possible for the raft. I was just thinking of a perforated pipe in the middle of the bed, plumbed to the next bed. Should i not perforate and let it siphon the cleanest water from the top and they'll each level out? I have a laser level to ensure everything would be at the proper level across the whole setup. I have lots of leftover lumber from other projects so I was planning building wooden beds 4' wide 8-12" deep and lining them with a duraskrim liner. So each bed I add that is the length of the pond would add an extra 1000-1500 gallons to the system depending on how much is gravel vs raft. I might start with one bed and add the other after the fact once I'm up and running unless there is a reason not to.

What would be a good stocking rate for something like this? Especially since koi are so expensive I'd rather buy them as peanuts or 3-4" so that I'm not spending a fortune. I've seen some horror stories of pump failure and fish die-out so I'm planning some alarms and failsafes there but I was also hoping that a pond this big would allow me some time before any issues like that.

Am I crazy or is this doable?

Welcome!

Aren't we all just a little off our rockers??
But, isn't that what makes things fun??

Sounds like you've put some thought into your plans. I have seen a few air lifts that appear to function quite well, but I don't know if you will be able to turn the water volume over at the rate you might want. I have zero experience with them. But try to find a tried and true design that has been tested. Do you already have a design in mind?

Your plan does have a large water volume. And established systems do seem to eventually compensate and are resilient if things aren't 100 percent perfectly meeting all the magic numbers. I know there are people who don't quite turn over their water volume in one hour, and the systems are fine.

I think your idea of starting with half of the proposed system is a good idea. It should be able to let you start with less fish , then as they grow, you could expand once they produce enough waste to run the larger system. Plus, it will let you adjust/ fine tune things, and whatever learning curve you might experience.

I don't know what would be best in your situation regarding the gravel beds being connected or not. You'd probably be ok if each gravel bed was independent. One thing that might work would be doing one with a bell siphon and one continuous flood. Or you could always have the option of running them all continuous flood. If I was connecting two beds like you mentioned, I'd worry about roots blocking the connection pipe. It might never happen, but if it did????

If it is two gravel beds, one after the other, maybe the first one could be constant flood, draining into the other bed if they were positioned at different heights. Or they could each drain into the troughs via a shared drain pipe under the beds.

You might consider a solid settling radial flow filter or similar before the gravel beds to prevent solids from building up too fast, which probably wouldn't happen for a while, but it would ultimately probably keep your dwc cleaner in the long run. I have an rff on my inc system, and it catches a fair amount of solids, but there are still quite a few that make it tough the gravel bed and into the sump.

If your gravel beds are going to flood and drain, then make sure you factor the water volume that would enter into your dwc troughs, and make them deep enough to handle the fluctuation.


When planning for fish density, there are some specific ratios to consider, which I don't know off the top of my head. But, I believe it's usually based on the fish weight when grown out. Something like a pound of fish per 10 gallons of water. There is a number thrown around for grams of food needed to sustain numbers of plants. I don't know that one either. But, i would think this matters more if you are going to be doing this commercially. And usually there are some deficiencies or needs for inputs when the fish are young if you are trying to support too much plant matter in the beginning. It depends on what you are growing too. Apparently, lettuce/ leafy greens have the least nutrient requirements, so might be better to start off with. Koi would be a fine fish to use.

I'm sure someone else will chime in, but that's what I could offer. Keep us updated on your progress, and post pictures if you can!

One thing I recall about air lifts is that they function better in deeper water. But I think three feet might give you enough pressure.

Thanks for the advice and encouragement! The radial flow filter looks easy enough to set up so I'll probably do that as well then. I was trying to decide between Glenn Martinez's setup and the Dutch guys on koiphen. Glenn's seems to have a much higher head and doesn't seem to require the depth that the koiphen setup does. I like the idea of the low power pump, the extra aeration and the ability to handle some solids so I'm hoping to get it working but we'll see how it goes.

Had never thought about roots blocking a drain. Good call.



How would this work for something with so drastic a size difference? If I'm ordering 1-3" long koi that will eventually be 25lbs after a few years, it doesn't sound like the system would be feasible initially. I figured I'd start with lots of littles and then sell that as they grow if need be. Do they produce a much larger amount of waste while they're growing or something?

Do you know of a good source for the stocking info? I feel like i've seen numbers all over the board. Thanks again!

I'll be sure to add plenty of pictures once I get things under way

Also, what sort of turnover rate are we shooting for? 1x per hour?

I'm now seeing that a lot of setups have far more gallons in plant production that for the fish tank. Is that ideal as well? I guess I was thinking of a lower stocking rate but more water. Would that work alright too or should I shrink the pond to make more room for grow beds?

Also I did a total crap job of explaining how I was going to transfer from bed to bed and back to tank but this is exactly what I was thinking. Glad I found a post for it here

viewtopic.php?f=8&t=4086

I think that nutrients can be diluted in big water volumes, and fewer fish. And yes, as the fish get larger, they eat more, and produce more waste. Plus, little fish make little waste, big fish make big waste...

As far as the system being feasible initially, just keep in mind that it takes time for the biology to develop, and that a lot of people see deficiencies in the first year. Sometimes these go away as mineralization starts to occur in the gravel beds. But that might be something to think about too. Maybe you could add a mineralization tank, which might help recover nutrients that would otherwise leave the system.

I don't use one, but a lot of people do, and it seems like a lot of the commercial ventures do.

It seems like UVI uses something like 1 lb of fish per 5-10 gallons.
It seems like a lot of APer's err on the side of caution and keep 1 lb for 7-10 gallons of water.
It seems like a lot of people who want fish production for food try to push the limits, and go with the higher densities, but there is much more risk in doing so if something goes wrong.
It think you would be fine at 1 lb/ 10 gallons.

Most people aim for turning over the water volume in one hour.
You could probably get away with a smaller pond. It would concentrate nutrients in less water. However, a larger body of water will be more stable over time, changes will happen more slowly, whether it be temps, ph, etc.
It would give you a great thermal mass though.
But I think a 2000 gallon pond might work just as well as a 4000 gallon pond.

A lot of systems are plant focused in their production. With fish as a bonus. I think the systems you are talking about fall into this category.
Too low of a stocking rate, and the plant aspect will suffer.
Some are fish focused, with plants as a bonus, and as a means of dealing with fish waste.
When you have raft beds, in my mind, it's kind of like an extended fish tank, just that the fish can't access it, but it further dilutes nutrients in the water, and also adds to the stability factor. I could be wrong, but that's how it makes sense to me. You could probably get away with a smaller pond.

Do you farm commercially?

So are you talking about using a bridge siphon between the raft beds?

I am using one between two tanks that i use as a sump, and i works great. I used to have problems every once in a while with and air lock developing in the high part. And it was really challenging to dip the siphon to fill with water, and keep it filled.
I think you would probably be okay with running a pipe or two between the walls to connect them. You would have easy access to inspect them, and clear anything out if needed. I was thinking initially that you were taking about the gravel beds, where inspection of the connector would be a lot more tricky, and where there is higher likelihood of growing crops with massive roots.

To fix my bridge, I ended up using Web 4 Deb's idea, and added a small ball valve to the top of the siphon. It works great, every once in a while, I just have to open it, and suck on a clear tube until water exits the valve.

This free online publication from the Food And Ag branch of the UN, has a section on calculations and ratios.

Small-scale aquaponic food production Integrated fish and plant farming

http://www.fao.org/in-action/globefish/ ... 0ecosystem.

Grew up on a 2500 acre cash crop farm and have always enjoyed raising plants and animals so I'm not new to farming but new to aquaponics. I would say I'm definitely plant focused but the fish are a BIG bonus. My wife and son will be enjoying it too so I'd love to have clear(ish) water to watch them for their enjoyment. We'll have a small sitting area in there to enjoy it especially during colder weather.

That being said I definitely want the plants to thrive and I want a lot of them. I might dig the whole pond while the skid steer is in there and only line half of it to start so that I can have a higher density with the smaller pond. I was thinking about using the bridge siphon but am open to alternatives.

Thanks for that resource Mgessert!

Trouble free stocking would be 1/4lb per us gallon, grown out size.
Filter beds need to be 25litres of wet media per grown out fish.
A solids filter would really benefit this set, aRadial Flow Filters are the best option, solids from these will be collected and added to a mineralisation set up for the supernatant to be added back for the nutrients. the smaller solids will get filtered out by the media beds, worms will benefit these beds as well.
Koi are fantastic fish for AP, i used them to great success, there basically pigs with fins, a bit mucky though, so filtration needs to be good.
As for the beds multiple inlet points will make them more efficient.

Very cool. Thanks @dasboot. Here's my second iteration on the plan. Added the radial flow filter and will probably add a second for the other bed. I'll just start out with one side filled up and once things are running smoothly I'll fill up the other side.


Thanks for the tips on the stocking density. How do I stock it if I'm starting with peanuts though? Get the large box of 100-150 and start to sell them off or add more beds as they grow? Koisale.com seems to have pretty favorable reviews from what I've seen online does anyone here have any opinions on them? There is a local farm that stocks koi, trout, and all sorts of others so I could call them as well but I was hoping to get some of the more premium koi to see if I can resell any down the line.

When i bought my Koi fingerlings i bought the cheap not so brightly coloured ones, the shop actually had a deal buy 10 get 1 free, so bought 80, that shocked him. As they grew some of the coloured up lovely.
The bottom line though as these were to power my system, i didn’t actually fret what they intially looked like.
https://fb.watch/2Obfert8rc/

Update on your design looks great, flow rate and retention time will show you if you need a second RFS.