aquaponics / revelations / veggie garden

We will do science to it!

…and hope for balance and harmony

Everything seems to be going OK with the aquaponics system. I think we have hit the aphids on the head, although I do have a rather awesome batch of Tomato Nightshade Tea ready and waiting if new troops arrive (faint echoes of evil laughing…). We have been happily watching the fish actively feed—the Jades swim around in a group and then courageously break the surface in a whorl of bubbles, snatching the floating pellets and then descending, wheeling around and then back up again for another strike. The Barra are ever so much more laid back…not so interested in the sprinkle of food as much as finding a pozzie on the pump for a sleep—odd, but probably very in keeping with their Aussie heritage.

We have been taking readings on the water for pH, ammonia, nitrites and nitrates from the get go. These, and dissolved oxygen levels, I believe run the system. In a nutshell: we feed the fish; they poo and wee and create ammonia; this is cycled in the water to the grow beds where one type of bacteria break the ammonia down into nitrites; then another bacteria break that down into nitrates; the ‘cleaned’ water is cycled back to the fish. Nitrates, along with other elements, is what the plants take up and makes them flourish.

If the water is too alkaline (high pH) it is no good for the fish and definitely not good for the plants—too alkaline and nutrients in the water are not available. If the water is too acidic (low pH) it is not good for the fish. It’s a balance. We are trying for 7 (neutral) to 7.2 until further research tells us otherwise.

Our brassicas (the broccoli) had some odd patches on them, so we took a leaf sample to our friends at Aqua Gardening (, the people from whom we originally bought the IBCs. They suggested it was a potassium deficiency which was making the leaf susceptible to sunburn. So we now have a powder to add to the water to fix the potassium, but this will raise the pH, so we have a potion to bring the pH down. Our tests also tell us we have a nitrite bloom (5 is too much according to the experts) and so we are going to dose the system with powdered bacteria (who would have thought that was a product!!!) to help the system along. It’s all a bit of a chemistry experiment, but as long as we don’t do anything too suddenly we shouldn’t have any catastrophes.

…and as at 3.30pm today…no rain but some promising looking clouds on the horizon!

One thought on “We will do science to it!

  1. Closed systems are shakey at the start but once you nudge them in the right direction it should be stable for a long time at the right levels, glad you’ve got some guys over at AG that can help you along the way!

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