Aquaponics 101 – Ups and Downs

The beauty of an aquaponic system is that it is a little eco-system, and looking after this eco-system has certainly given me a new appreciation for the delicate balance of nature on Earth.

Both the plants and fish are thriving. I have had one more “jumper” and another one in the tank acting strangely, but other than that they really are pretty hardy. I am still fighting ammonia spikes but have got the system down to a T. I am testing the water every 3 – 4 days. If the ammonia and/or nitrites are high, I do a partial water change and stop feeding for a day or two. If the ammonia is dropping. I increase their food somewhat. They should be consuming about 3% of their body weight daily but are getting nowhere near that.

My problem, as mentioned previously is that I just don’t have the correct ratio of grow beds to water. To balance the system nicely I need to double my grow bed (and plant) volume and/or add a bio-filter.


On the plant side the “gem squash” has turned out to be butternut and has flowered and fruited like crazy. The beans are going mad and have just flowered today. Tomatoes (3 varieties) are all growing slowly, but nicely. Parsley, chili and other herbs all doing well. Strawberries are battling a little because they are getting overgrown by the butternut.

Here is the butternut which is threatening to take over the neighbourhood.


And the baby butternuts forming.


The bean plants.


I have treated the system with Iron Chelate because iron is the only element not present in the fish waste. I noticed a problem when the butternut started flowering and treated immediately, and will do so at three week intervals.

The loop siphons to drain the grow beds required too much maintenance and I am losing patience. I installed a pipe within pipe bell siphon in the little goldfish system and it is working flawlessly, so it looks like I’ll be converting all of the grow beds to this method. The only downside is that it requires the pump to be cycled (15 minutes on, 15 minutes off) The fish should be OK with this because I’ll have the air blowers going all of the time, but I’m not sure if the pump will hold up to this constant cycling.

This is what the loop siphons look like;


And this is the tube within a tube bell siphon that I want to change them to;


On the subject of the pump, it has developed a small leak at it’s base. I will need to return it to the suppliers to be checked out but cannot take it out of my system for that period of time so it looks like I’ll have to buy a standby pump, which I have learnt from the oyster business, is a good idea to have anyway.

I am going to be presenting a basic one-day course entitled, “An Introduction to Aquaponics” soon in Knysna. It will include a theoretical background on all of the basic principles, a discussion of various systems, hardware, fish and plants and then a hands-on session of system design, construction and maintenance. I am limited to 8 delegates at a time, so if you are interested please send me a message.

Anyway, enough for now.



5 thoughts on “Aquaponics 101 – Ups and Downs”

  1. Hi, I’m working for the Department Of Agriculture in Limpopo and would like to attend one your coarses on Aquaponics. I’m currently in Aquaculture and very much interested to learn more about this.

  2. Hi Patricia,

    I am based in Knysna and we will be running an Introduction to Aquaponics course in mid to late April 2008, I will email you closer to the time.


  3. My father and I have started farming tilapia in the Sedgefield area and I would like to attend a course, but cannot travel too far from home. I am particularly interested in breeding techniques. Please send me details. Many thanks. Catherine.

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