My Aquaponics Journey so far

[Ria Follett]

Ria’s aquaponics journey

As part of my aquaponics journey, I have been experimenting with setting up my own system. This is my story so far.

I love challenges, so I gave myself a real challenge, by building the system in the forest that is my backyard. So I only get 3-4 hours sunshine which is not ideal for vegetables. Almost all vegetable seeds I find in the shops say “full sun”. Other gardeners say that green vegetables will grow in shady conditions, but not fruiting vegetables. We will see. I don’t have a choice with an alternative sunny spot.

My first attempt – a potential disaster.

I dug a pond in the garden and lined it with heavy duty pool liner for my fish. I covered this with mesh to stop the birds from eating the fish.

I bought a blue barrel, cut into two for my grow beds which I placed on cement blocks. I added a blue metal as my grow media and covered this with a thick layer of clay pebbles. The growbed was covered in net to stop the possums from eating the plants. My backyard is a haven for wildlife.

I dug a conduit from the house to the pool, installed power points, bought a pump and added the plumbing and standpipe. I decided to start by using continuous flood, since this seemed to work based on a study done by backyard aquaponics comparing the various methods.

I also decided to cycle with seasol (a liquid fertilizer made from seaweed) for 3 weeks, and then add fish monitoring the system carefully.

So I was up and running.

After a week I noticed that the blue barrels halves had bowed out to a dangerously. Will they collapse? Just imagine, if they do, the pump would continue to pump water into the “barrels” which will then flow over the ground, and continue to do so until the pool was empty, with both the fish and pump dead.

My problem was that I saw many pictures of systems using blue barrels as the growbed, but didn’t realise that the sides needed supporting as well as the bottom, to stop the sides from bending out.

Second attempt – a better start – still lots to learn.

I decided that I needed to be absolutely sure that my growbeds won’t collapse. So I decided to build them directly on the ground, with brick surrounds, and another pool liner to keep the water in the grow bed. Because this brought the grow bed only just above the pool level, I placed it so that the drain was over the edge of the pond, and drained directly into the pool with no pipes.

So I was up and going again. In fact I now have a nicely landscaped system. The blue barrels aren’t very attractive.

My cycling continued and worked exactly as expected. After 3 weeks I added 16 silver perch. After 5 weeks nitrites appeared. Nitrates followed at 6 weeks. After 7 weeks, the nitrites disappeared, and I haven’t seen them since.

I tried a number of different plants, with limited success. The beans and snap peas did OK. The broccoli, cauliflower did fine until they were attached by aphids. Surprisingly I had no success with lettuce. So there is a lot more for me to learn here to improve my harvest.

However my silver perch seemed to have disappeared. They didn’t seem to eat the food I added. I never glimpsed any sign of them. The perch are grey, so hard to see on a dark grey liner. I didn’t see any dead fish floating on the surface. Maybe the fish are living off dead fish?? Maybe the ammonia in the water comes from decomposing fish food? Eventually I decided don’t have any fish in the pond, so I decided to restock. Just to check I emptied the fish pond. When it was almost empty, I saw some flapping – and was surprised to find that all of my fish were alive and well, and had in fact doubled in size.  So much for no fish!! So I refilled the pool with rain water.

It’s interesting how the chemistry tells the story. When I refreshed all the water the nitrates disappeared. They returned within a week.

I also seemed to lack iron, so I added some iron chelate. I also had fairly high pH levels, which would have contributed to the low iron levels, so I managed to reduce these to around 6.4 and keep them there.

At one point I decided to cover the pond. Most of the systems on the forums seemed to cover their fish tanks. I had already added 2 air stones, so I assumed that covering it would still deliver enough oxygen. So I covered it with a plasticised canvas. Within 2 days I found 3 dead fish floating. I can only assume that this was caused by the covering, so I removed the covering and no more dead fish. I did lose single fish on a few later occasions.

I also switched to flood and drain by adding a timer.

Extending the system

My nitrates seem to be growing steadily and reached 80. I decided I needed to grow more plants to use up the nitrates, which meant adding another growbed. One of my blue barrels wasn’t bent as far out of shape as the other, so I added this half barrel to the system and filled it with clay pebbles.

I also noticed that my pool did not get warmer than 72⁰F/ 22⁰C even though we had quite a few days of temperature over summer over 95⁰F/35⁰C. Silver perch are supposed to grow better when the temperatures are above 73⁰F/23⁰C. They take a long time (18 months) to get to plate size, so if they grow slower than they are supposed to it would take forever. So I wondered if I was better switching to trout. In the end I decided to add trout to the same pond as the silver perch. The silver perch have small mouths and can’t harm the trout fingerlings, and provided I feed the trout adequately they will probably leave the silver perch alone. Otherwise I guess I have provided just another source of food for the trout. I will see.

Before I added the trout, I decided to check what fish I had in my system (I still couldn’t see any fish in the pond), so I emptied the pond again. Yes I did have 9 fish of varying size. I refilled the pond and added 10 trout fingerlings to the mix.

I have enjoying the journey and there is still a long way to go. I also appreciated logging my progress in a diary, so that I can look back at what happened. If you think that logging to a diary is useful for you, you can use the same one as I do – on www.ourresearch.net. If you join the site you can also view my diary and other diaries to learn from them.