Backyard Aquaponics
A place to discuss aquaponics

Hi everyone!
I'm Maayan from Arad, Israel. I am new to aquaponics but used to be an avid aquarist so fish keeping is the easy part for me...

I have been lurking the forums for some time now and finally decided to get my (husband's) hands dirty and make the plunge. So I decided to go with 2 ibcs in chift pist style, but I am still on the fence about some things and I would love to hear your inputs.
This is intended as a test system, something to grow from, to test the waters so to speak. I have every intention of growing all our family's food needs myself and so would definitely expand later on but I want to start small and slow so that if there are any faults at least I won't be losing too much.

My location offers some unique challenges:

* I live on a mountain 700m above sea level, in the middle of the desert so weather extremes are quite a hassle.
In the summer we get up to 43c during the day and down to 30c at night. In winter we get as low as 9c during the day and 4 during the night. Snow is uncommon but for the past two years it snowed three times (never lasts more than a night and over 2cm deep though).
As I live over a wadi (shallow canyon) my plot is also wind-ridden.

* Critters are an eternal nemesis of my garden; rock hyraxes climb on inpossible walls, get through the smallest cracks and eat everything. EVERYTHING. Even cacti and succulents.
What the hyraxes won't eat the porcupines do. They even ate my pallet gate two nights ago.

The good news though, is that my husband works in a recycling company that cleans up IBCs and barrels so materials are free

What I came up with so far is this:



Two IBCs cut to 700/300l pieces.
One 700l piece would be the tank, one the sump and two GBs totaling 600l of media.
I am following the 1:1 ratio (because 1:2 is kind of not feasible, too little space for planting but I figured with the sump it evens out).

Stocking fish would be at the recommended 2kg per 100l or less (I am still undecided on fish, need to research growing conditions. I am aiming for the least energetic input possible), for now I will start with goldfish since they are cheap and locally available.

GB media would be scoria -- cheap, available.

My greatest inner debate is whether to go with constant flow or flood and drain method.
From what I'm gathering, F&D is what most people here are using and I am not sure why. As far as I can see it requires a larger pump (more money), you have to play with siphons and I've heard of people whose timer died, which provides another (seemingly unnecessary) weak link in the chain.
Cont flow on the other hand, as far as I see it, is pretty straight forward, requires a smaller pump, less tweaking, aerates the water better and is generally more user friendly.

I would love to hear your input though, what do you guys use and why? What is the good in it? What is the bad? Which one would you go with if you were starting out again today?

We are renting so burying IBCs is out of the question but we have a great place for the setup, in the front of our house is a 70cm ledge. The lower part (on the same level as our house) holds our current struggling veggie garden (due to the wonderful critters previously described). This is where I thought to put the sump for gravity.
Straight above it would be the FT and next to it the GBs.
The pump will pump from the sump to the FT, an SLO will then get the water out to the GBs which will be connected through the drain and drain into the sump.

Because of our lovely critters (protected species too! Can't do anything to them) I would prefer to have my GBs as tall as possible, so I will be laying several pallets under them but still make them lower than the FT (obviously) but I am wondering if it's not too low.

A different setup that crossed my mind is either set up two individual cont flow systems where the GB sits on the FT, because of the benefit of the height of the GB, but that has a big downside of lesser water volume, i.e more system vulnerability (so this idea was ditched quickly) or somehow link the two FT together but I don't see how that could be done and I would have to have one GB drain to the "sump" and.. don't know, scratched that pretty quick (but if you have an idea on how to do this I'd be happy to hear!)

So, I would really like to hear your thoughts, ideas, constructive criticism and opinions.
Like I said, I am just starting out and although I read a lot, there is nothing like hands on experience.

Thanks in advance!

Welcome to the forum!

I guess the first question I'd ask before I could even attempt to offer any advice is "given that you're on a mountain and over a wadi, what kind of change in elevation/slope (if any) are you dealing with on your site?" I'd also be curious (by which I mean "worried") about whether you ever have to deal with flash floods in your wadi. Granted they're usually dry river beds (at least the ones I know about), but even way over in the middle of the Sahara Desert they tend to flood every generation or two...

Again, welcome aboard!

F&D with an auto siphon is very similar to constant flow. The pump is run continuously and the siphon controls the flood and drain cycle. When the water level rises above the stand pipe, the siphon empties the growbed faster than the pump fills it and the water is drained. The pump never stops. If you build your system with siphons, you can always just pull the bells and they will operate identical to a continuous flow system.

The systems that flood and drain on a timer operate in a different way. The fill port is at the bottom of the grow bed and when the timer turns the pump on, the bed fills up to the level dictated by an overflow standpipe. When the timer turns off, the growbed drains through the same fill port and through the pump. There are a few drawbacks to this method but the benefit is very simple plumbing.


The grow bed does not need to be lower than the fish tank, just lower than the water level in the fish tank.


This is essentially the system showcased in IBCofAquaponics. See the link in the top bar. The downside is as you said, more system vulnerability and you won't be able to expand the system with many more growbeds before you have issues with lowering water levels in the fish tank.

Thanks!

Where I intend to place the system is level, so that's not a problem.
The entire plot has two levels but in and of themselves they are level.

The wadi itself does fill with water in the "rainy season" (one or two weeks a year) but that's a few dozen meters below us and doesn't affect us in any way.

Our desert is a rocky one.

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Oh, I didn't realize that. Thank you for the explanation. Simpler plumbing would be nice, but which one do you think is better?



Yeah, that's what I meant.



Yup, so not really an option.

Thanks for all the input!

I've used the traditional flood and drain in a hydroponic system and found that it is hard on the pump. Turning on and off all day long is worse than running continuous and the drain cycle deposits a lot of crud in the impeller and that's with a hydro system where there is not nearly as much solids.

For aquaponics, I prefer the auto siphon. They are dead simple and with proper design and a little preventative maintenance, they will never fail you.

As a test, I pulled the bell in one of my beds and it is now running continuous flow. I found that seedlings had a harder time with many wilting and damping off. The one that survived are growing at pretty much the same rate as the auto siphon bed beside it.

Good to know. That's what I was also thinking, the on/off for a machine not designed for it would kill it more quickly.

What is the size ratio between your pump output and your drain?

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Having built a VERY similar system to the one proposed, I feel that I should make my thought known..

Firstly, I had constant flood, and then went to Timed-Flood and slow drain, and then finally, to Auto Siphon.

Which was best - NO DOUBT - The Auto Siphon

WHY - because ONLY the Auto-Siphon gave a serious "Flush" to the fish tank and thus gave me a chance of moving the solids.. and even then, it ain't all that great at it anyway..
I have abandoned that system to serious AP, and built a ROUND TANK system, which is heaps better, as I can keep the FTs clean..

and at the risk of sounding like a broken record, I would seriously include a solids-filter, and remove the solids to where they can be safely processed and then either used in other gardens, or re-introduced as clean nutrient liquids..
..
.

I'll look into that, thanks!

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It's starting!
1000 litre ft, 1000 litre sump, 4 x 350 litres gbs.