Backyard Aquaponics
A place to discuss aquaponics

Sandra and I live in a harsh desert environment. We've tried planting fruit and vegetables just to see them grow beautifully until a stiff hot breeze comes by frying everything in its path. One good cooking is all that's needed to ruin all hopes of harvesting anything worthwhile.

We've decided to try aquaponics but even that has its challenges in this environment. In the summer time we will see a week at a time of temperatures well above the 45°C mark and then in the winter time the mornings are likely to be below 0°C for several days at a time.

I decided to try to keep the fish below ground so that the temperature would remain more stable. Digging a hole proved to be quite difficult.



The cap rock is about 200mm down so even with a jackhammer it was going to take forever.



We decided to buy our little CAT from the auction. We've always wanted a toy like this so now was opportunity to get one.



Of course when you dig a big hole there's a lot of dirt to get rid of and it took a dozen trips to the dump and an awful lot of shoveling. The next thing on my list will be a tipping trailer



Before long we had a very big hole in the back yard.

This is my first go at posting our story so hopefully it'll work.

Welcome! That's a good idea. Keep us posted. You are gonna need some shade cloth too.

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After placing heavy railway line around the edge of the driveway I needed to stabilize the pond sides so I mixed some concrete mortar and sprayed the surface.



The mortar didn't have much strength so I mixed in glass fibre reinforcing and laid another layer with a trowel.



It looked ok but had hundreds of hairline cracks so I sealed it with a coat of liquid rubber.



It took a lot of time to brush in because my concreting skills are/were quite limited



Mrs M kept me to a promise I'd made years ago. I told her if ever she got a pond I'd build a bridge over it. Those home & garden magazines have a lot to answer for



After doing a little Googling I took notice of somebody's advice that a black tank would hide our fish



Mrs M painted the bridge so got to choose the colour, not a colour I'd have chosen but I like it.

Yes Rcmaveric she has that job already on the whiteboard for me

We've got to a point of getting the pond ready for water. I've installed a ladder at one end so that I can get in and out if needed.



I applied two coats of pale blue rubberized paint so that we could see the fish. Mrs M's bridge is not quite finished but it's serviceable. They recommended leaving the pond coating for a week to cure fully but we gave it a month and hosed it down a few times.

The plan is to lightly stock it with fish because we spend a lot of time away. I don't want to be tied to the house so it must be low maintenance. When filled it will contain 10,000L but we haven't got that far yet.

They make pond autofeeders. The fish can go a while without eating species and water temp depending.

Looks good so far.

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Just checked them out on Amazon. That would certainly resolve the feeding problem if they are trained to eat processed food.

With the coronavirus lockdown it seemed the right time to get started with our fish. I did a bit of research and it seemed like barramundi would be ideal in our climate. They are a native fish in the streams nearby, (we don't have any streams) will handle a good range of temperatures, are easy to feed and are not too fussy on the water quality. The problem came when I was advised to have several tanks where fish could be graded by size so they didn't eat each other. I can't be bothered with barra.

I didn't want imported species because it just goes against my grain so that ruled a few out. The best option then seemed to be silver perch. I called the supplier in Geraldton and was quoted $4 - $6.50 for fish 100 - 150mm. Then I had to work out some way to freight them from Geraldton nearly 500km to Cue. The other option was to take a leisurely drive over a couple of days. Either way it looked like being an expensive exercise with little chance of healthy fish arriving.



The best option I could come up with was to try to catch some local fish. We don't have surface water anywhere but there is plenty in some of the abandoned open cut mines. With the temperature into the 40's we took our goggles and went for a look.



The first water hole was great. The temperature was perfect and we spent hours snorkelling about but there wasn't a fish in sight.

In these little country towns nothing beats local knowledge. Accessing that local knowledge, well that's another thing so it took me a few weeks to bleed the information I needed from some of the old-timers in the area. The next old mine they told me about looked more promising.



I spoke to the pastoralist and he informed me that they were in lockdown but I was welcome to jump the fence near the mine. I did and It was a spectacular hole and obviously much older. As soon as the fish trap hit the water several good sized spangled perch circled about taking a close look. I came prepared with a 200L drum in the van about a third full of water. Those smart little fish were just pulling my leg. They had all night while I camped out in the van but when I pulled the trap in the morning all I had was two yabbies.



I couldn't admit defeat and go home without fish so I spent a while browsing the map to reveal another similar abandoned mine just a kilometre away. It was a long walk in rough country but I had all day. It was another spectacular water hole, steep on the sides and reedy on the ends. The fish were a bit smaller but smart enough to find their way into the trap (or not smart). By late in the day I felt like my arms were two inches longer. I'd walked a kilometre back to the van carrying six fish in 15L of water. To make it worse I still had to return to get the trap. I did the two kilometre trip again but this time I returned with seventeen beautiful little spangled perch.



Every critter was measured and weighed. To say I was excited was an understatement. We ended up with twenty three spangled perch and two yabbies. A successful fishing trip.

Congratulations!! Did you all ready cycle the fish pond? I have no experience with those fish, but have you looked up how to feed train them?

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No Rcmaveric. We're definitely Newbies. I put 800L of tap water into the pond before I left just in case I caught some fish. When I got home that night we spent a while weighing and measuring each one before dropping them back into their original water. The very small one was 70mm and weighed 4g. The largest was 210mm and 116g and all the others somewhere in between. The yabbies were both 100mm and 23g and 26g. we had just over 1kg of fish but they looked to be more.



I drained the 60L or so of the muddy water from the drum into the pond and sat the plastic bags in the pond with the top open. After half an hour (well perhaps 15 minutes) I upended the bags.



I pulled some of the bulrushes out of the pond while I was there and added them to the water I carried home.



That's why the previously crystal clear pond water came home a muddy mess. With no other plants in the tank I thought it might give them something familiar.



By morning most of the mud in the water had settled.



At least everybody was swimming around.

Hello, Did you find any gold????
I love the methodology for building the pond. I hope your fish do well.
I was just looking into liquid rubber the other day, I'm trying to turn an old wooden hot tub into a pond/ fish tank, and was considering this route. Nice work so far!

Yes Will, I married a gold digger. She can sniff it out from 50 paces

I went looking for liquid rubber but ended up with an elastic polymer that seemed to be perfect for the job. The first couple of coats are the black RTT Sealant and the next two coats are blue.



It feels a bit like it never sets but the surface is sealed. I'm really happy with the tough pliable coating. It has certainly sealed the pond.

I'm flying blind here but slowly edging forward. We don't have any growbeds setup but we have an old bain marie that I picked up at CueBunno (our local dump that's sometimes better than Bunnings).



We used 6" PVC for the stand and stood it in place before we built the greenhouse.



It's like an oven in there so now we're putting up a shade sail over the top.



Today I had a crack at assembling a remote siphon. We can't buy plumbing fittings here so I bent a piece of PVC with the heat gun. It seems to work well but we'll see when it's connected to the growbed.

We started out with 23 wild spangled perch but lost 4 after a couple of days.



They had big blotches on the sides and one had a white eye. The biggest one has a white eye as well but that one is still ok and I think the eye is coming good.



We only had 1000L in the tank at that stage so I added 2 kg sea salt. I'be been filling the IBC with 1000L at a time and putting it at 500L at a time after it's stood for a couple of days. We now have 3500L in the tank but I've noticed some of the other fish have blotches on the sides as well.



I setup the filter using shade cloth and mosquito mesh inside. I was pumping with the Davey pump but the pump jammed up with little leaves. My Polysphere filter balls turned up today after 10 days on express post so I set up the submersible pump in a wire mesh cage and started cycling the water.



When the pond is eventually filled with 10,000L the Orange submersible pump will draw from this hole. Hopefully it'll draw all the floating debris into the leaf filter above it.

My remote siphon worked but the pipe from the growbed to the remote siphon was too small. The siphon would start and then empty before the water in the growbed emptied.



I was surprised at the flow rate of the little tube. I ended up bending a smaller tube and now I've inserted it into the growbed instead of in the remote bucket.



When I tried to buy expanded clay I found it quite expensive but the freight to get it here was even more. At $45 a bag just for the freight it looked like blue metal off the main roads pile might be the way to go. The weight of the blue metal sitting on the deck worried me so I decided to take a trip out the bush and came back with about 50L of scoria.



I'll use the scoria in the bottom of the growbed and then I ordered 5x50L bags of expanded clay to go on top. If I need more scoria then I just head back out and get as much as I need after all the price is right. I've chosen bigger pieces so that I can easily separate it from the clay later if I need to.