Aquaponics 101 – good progress

If you can find time to do something twice, then rather do it properly the first time.

18 hours of hard slog and we (Joshua and I) have now completely rebuilt both the back and front terraces that were damaged in the rains. This time I have re-inforced with concrete and cross supports so hopefully it will hold, but who knows with these rains and the clay that I am working with. This is what the rebuilt terraces look like now.


And here is a top view of the terrace ready for the concrete slab. I just need to spend some time on clearing and getting my levels just right.


My next task is to lay a concrete base for the greenhouse. It will be 100mm thick and 6m x 4m in size. I have to start thinking about where I can get 5800L of water, so last week I went out and bought a 2500L water tank. We built a base and after much heaving and pushing (and swearing) eventually got it into position. The whole one side of my roof (about 200sq/m) will now drain into my new tank.


Damn, there are big rains coming and I won’t have the gutters and downpipes ready in time to catch the water.

I think I am going to use another of these tanks as my sump which will be at the bottom of the garden. The water will flow by gravity (overflow) from the two fish ponds over the gravel grow beds. I am designing them to be flood and drain. In other words the beds will fill up with water and then drain out with a siphon system. This sudden rush of water out of the bottom of the grow bed then sucks oxygen through the gravel to the roots of the vegetables. This water leaving the grow beds then flows into the sump. From there it is pumped back up the hill to the fish ponds and the whole cycle repeats. I am aiming for a flow rate that will move all of the water 3 times per hour ie. 5800L x 3 = 17400L/hr.

The “head” ie the height that the water has to be pumped vertically is 3m (1.8m to the level of the terrace and then 1.2 m over the top of the fish ponds. The pump will thus be purchased with these two factors taken into account (ie flow-rate and head).

I have been agitating about whether I should glue my PVC joints or not. Once glued it’s permanent so if I had to move the greenhouse I would have to cut it out. If I left the joints unglued the first big wind would tear the joints apart. Another idea is to drill through the pvc joints and pipe and fasten with a nut and bolt. Ingenious, secure and easy to disassemble.

Enough for now.



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