The idea is simple. Reared some marine life, be it fishes or shrimps, then channel the aquarium water to feed vegetables. Its a self-sustaining system which auto-irrigates your edibles while you are on holiday ! Sound great, right?
But this post took me the longest time to write, even though I told Ethan Phang ages ago that I love his set up and wanted to write a post on it. I wanted to understand more about how it work before actually penning it down. But you know what? The more I read, the more questions arose! 🙂 There is more to this than drawing fish water to the veggies bed, and I still don’t know the half of it, so please pardon me if I got some of the facts wrong. 🙂
According to Ethan, fish waste and water alone are not enough nutrients to feed a good yield of vegetables. There is a need to maintain healthy microbes growth which act as catalyst to break down different form of waste into minerals that the plants used. The plants will in turn filter the water so that the marine life can live in the same system.
To write this post, I sought out Xi Zhe as well, who built his own aquaponic system when he was 21 years old. I shall borrowed his “Nitrogen Cycle” diagram on the right, to demonstrate how an aquaponic system work (hopefully!) :
In the simplest layman’s term, fish waste and water need to ‘mingle’ with bacteria, where they are broken down into useful minerals for the plants. The result is nutrients rich water which will be drawn to the plants’ grow bed. The plants absorbed these nutrients, then act as a filter for the marine life. The cycle will continue with the help of pipes, timer, pumps and a bell siphon.
The next puzzle for me – What is a bell siphon and why it served an important function for such aquaponic system? 🙂
We all know as gardeners, that stems and roots should not sit in water too long , right? In soil based plants, we always used “well drained” soil to ensure that water are drained from the soil and the plants do not suffered root rot. So, it is the same for an aquaponic system. A bell siphon ensured that when too much water is piped up to the grow bed, this excess water does not sit around causing plant’s roots to rot.
This device is a mechanism to “cycle the water” said Xi Zhe. The “cycling” ensured that nutrients reached the plants while not letting the roots sit in water all the time. It is usually installed inside the grow bed, so that excess water will be discharged with the help of air pressure when water over-filled it. According to Ethan, a good bell siphon is one which self adjust to control the water level. I am sure a lot of trial and error are needed to get this to work right.
To doubly ensured that his plants’ roots do not sit in water, Ethan only allowed 2 inches of water to cycle in his grow bed at any given time. And then, where his plants sit in the grow bed, there is at least 2.5 inches gap between roots and water so that the roots can breathe.
Want to know why Ethan’s rosemary is thriving here with the rest of his edibles? 🙂 To ensure that his grow bed work well for different plants’ needs, whether thirsty or dry loving herb like his Rosemary, Ethan’s plants are not planted directly in leca balls. In fact, on closer examination, every plant is individually potted in soil as well. For drier loving plant like the rosemary, the pot is higher away from water source. And that’s how he ensured that different plants with different water preference can be grown together! Ingenious, right? 🙂
The most difficult concept for me to grasp in this aquaponic system is how to breed the bacteria needed to break down waste into nutrients for the plants? Different gardeners used different methods but this is how Ethan did it.
He added worms in his grow beds!
Remembered his water level is kept low, only 2 inches height of water per cycle? As the water level is kept low in the 15 inches depth of leca balls, it created a perfect humid environment for the worms to thrive. The worms’ waste provide good nutrients for the plants as well.
Into the fish tank, he mixed the milky water from the aquarium’s filters for its nitrate microbes properties. These are the bacteria which will consume the ammonia released by the fish waste. The water which is pumped up to the grow beds are nutrients rich minus the ammonia.
Leca balls played a part too, as they are “good habitat to breed” the microbes and bacteria present in the water (Ethan Phang).. Both he and Xi Zhe agreed that when algae appeared to be growing out of control, you’d know the water is nutrients sufficient!
Ethan Phang designed his aquaponic systems this way, in layers behind glass tanks, to show how Mother Nature’s eco-systems work in sync to produce food. If we protect and guard every eco-systems carefully, Mother Nature takes care of itself, its a self sustaining cycle. Spoiled one part of it, everything falls like a house of cards. Thus, his aquaponic showpieces are not just to decorate an empty corner, they are “windows of nature” and carried an important message as well – Please, protect our environment!
Not all Ethan’s showpieces are big, some are tabletop size as well! Aren’t they cute? 🙂
Last but not least, Ethan Phang shared tips on how to keep aquaponic system as low maintenance as possible –
- Don’t exposed the tanks to direct sunlight
- Artificial lights on for maximum 6 – 7 hours a day
- Don’t over feed the fish
- Dont keep too many fishes in the tank, especially those that eat a lot, example: tilapia, koi
- Preferred shrimps or algae eaters
For a custom built of these sleek aqua systems, please contact Ethan Phang for quotation at firstname.lastname@example.org 🙂