Backyard Aquaponics
A place to discuss aquaponics

After seeing Joel on Gardening Aus the idea just stuck.. We had been given an old rainwater tank 2.5m dia. so we cut the top off at 1.2m high. We're only filling up to 2500 lt for now. It was hard to decide on grow beds, we liked the ones Joel did but had to get them up here ( 500k's north of Perth ). After inquiring at a local sheetmetal mob we bought these 2 tanks. It was cheaper to get 2 at the same time since we only needed half a sheet for 1 bed but had to pay for a whole sheet anyway.2 beds 2m x 1m x 0.4m $650. We now know that these should have been aqua lined but will have to deal with that in the near future( bugger, not looking forward to moving all that again, glad we used hydroton).
Had problems getting the two beds to fill up evenly.We used 40mm pipe because this is what we had. This time gb 1 filled up quicker next time gb 2 filled up first with no changes. Finally fixed this by having only 4 holes in each pipe/growbed.
The system was now ready.We got given 3 marron then threw a heap of seeds into the gb's and waited. We next bought 50 silver perch fingerlings. ( Just look up 'Fish dying in new system' to find out what happened next there )
Anyway, the system is up and running and now going good, just have to be patient and wait

One thing I forgot to say in the other thread, if you dont want to upturn the GB outlets because of noise, at least put a 90 degree elbow on the bottom to make the water in the tank swirl. Most fish love to have a bit of a current to swim against.

Cheers , like the idea. I think our tank has good aeration.2 x big air stones plus an extra splashing from the pipe in the centre for 10 mins every hr.The current sounds good will give it a try.

So how are you going to deal with the galvanized beds?

Good question.Any ideas welcome, you guys are a lot more experienced at this than us. Was thinking of waiting till first harvest then dealing with 1 bed at a time so as not to upset the system too much. What's the best way to empty a bed without killing the bacteria. Once empty maybe painting with a good pond sealer?
Have just finnished setting up a 3rd bed too. Hopefully post some more photo's tonight

Keeping it damp, but they may be easier said than done...doing one bed at a time, why not write off one load of bacteria filled scoria
e.g.
Empty one bed and seal
Empty bed 2 media into bed 1 and then seal bed 2
Empty bed 3 media into bed 2 and then seal bed 3
Fill bed 3 with bed 1 media

this way you will have 2 beds "bacterialised" at any one time and the 3rd lot of media won't take long to catch up

Food for thought. Got some photo's of the 3rd bed. As it's a different size and filled with 20mm gravel we'll keep this bed separate and leave alone to build up bact. This 3rd bed is lined with thick clear plastic. When we got this bed working we found out that we must have put a few small holes in the plastic, So the life span of this tank will be limited.

When using gravel, EDPM pond liner is about the only thing tough enough to survive - pricey though.

Have added a cover on half the tank to keep the fish happy. They are a lot more settled now.

After having this system running for a while now new ideas are popping into the head. We've sealed all our tanks made various changes and all is good.What I'm wondering about is changing our gravel grow bed into a marron/yabbie tank.
To refresh, system has 2 x 540 lt G/B , 1x220 lt G/B ( which will be replaced with a 600 lt bed) with 2000 lt in the fish tank. That doesn't include the gravel G/B this is about 760 lt
At the moment this bed is flood and drain, filling up the bed will be no worries, just unsure of the best method for draining( I know I need to keep constant water height). Is a venturi set up the best way or could i just modify the existing standpipe.
Most of all before I start Will this work, can anyone see any problems with this idea
Thanks Harri

Hay there. Good to hear that all is still going well with the system.

Please, share what info you have on how you sealed your grow bed!!!!!
What product did you use?
How was it to work with?
Any warnings you would give about said product?

This sort of info is regularly sought after around here.

As to turning the big round grow bed into a marron tank. Yes, I think you can simply modify the existing stand pipe into a good SLO drain of a sort (venturi drain in old time speak) Basically solid stand pipe up to the desired water level then around it, something like the bell off a bell siphon without the cap. Crenelations at the bottom plus some netting to keep small creatures from swimming up and going down the drain but have it higher than the stand pipe so the water is forced to enter at the bottom and bring the solids up with them and out the drain.

Thanks TC. Sealing the tanks we used an exterior grade brushable waterproofer.Says it's a heavyduty flexable compound ( are we allowed to give brand names?). It's for roof gutters, flashings etc.Bought at the local 'B' hardware. At first I tried to spray it on but the coats were too thin and it took too long. Best method was to brush on thickly with 2 coats.The fish tank did have a number of rust spots in it and they showed through 3 days after the spraying attempt.Re-did it with thick coats with a brush and all seems good. The future yabbie tank was given to us and had a number of rust holes in it about the size of screw holes. These were simply brushed over as the product is quite think and there's been no leaking at all.The real test will be when we emty the gravel out and have a good look at the empty tank.After the final coat it has to be left alone for a week before adding water( lucky we had the kids porta pool to keep the fish going).Been sealed now for about 5 or 6 months with no sign of deteriation.

I'm sure people would appreciate knowing what you have used and how it has worked. So far I've seen no one here get in trouble for sharing info about products. I think the only real rule is no advertising. And it would be in bad taste to try to compete directly with Backyard Aquaponics right here on the forum that Joel is so kindly hosting.

Yeh thought so but just thought I'd better check, this day n age n all.The sealer was called Crommelin waterproofing. Like I say so far so good, just got to get the coats on nice and thick. It is similar to the bathroom waterproofing you get but without the toxins. It is waterbased and can be used in ponds of various types.