Aquaponics


A rambling description of the growth of our aquaponics system:

Our aquaponics system has been a labour of love and remains a work in progress.

It started as a proof of concept with a NFT table (given to us by our friend, David MacKinnon), a bucket of water and an aquarium pump to circulate it (no fish at this stage).

That worked, so we moved to the media bed idea. That took but more effort – construction of the supports, finding and cutting the beds, cleaning the media and, of course, the plumbing (many $$$$$ indeed!).

Then we added a few fish – a few donated goldfish in a single tank.

That second incarnation was the NFT table and 3 media beds, the fish tank and a sump. All survived the winter in a DIY greenhouse.

DIY greenhouse

Proud builders of our DIY greenhouse

Deciding that it all worked well, it was time to ditch the greenhouse and add a fourth bed. The NFT table went later as well, to be replaced by bed number 5 and a second sump tank.

An extra tank was added to hold more water. It was planned to be some kind of filter, but it wasn’t effective.

Next came a pipe bed, running higher than the others along the fence.

Later we added a bed to hold lettuce and the like on a raft. This bed needed a constant flow because, with its addition, our pump didn’t have enough flow to satisfy a sixth bell siphon.

That bed was plagued with algae. To resolve it, it became a constant flow media bed.

Dutch Buckets

Dutch Buckets

Finally, four Dutch Buckets were added, supplied by the flow from the pipe bed and dumping into the sump directly. They will be for Sweet Potato in Spring. We had issues with the roots in a regular media bed and ended up hacking them out with a hatchet and putting the media onto the garden.

The Dutch Buckets have been taken down and replaced with a single tub for the Sweet Potato and Wasabi. All the pipes and stuff made the area look untidy and I’d made a mistake with the type of bucket. I didn’t realise that they were slightly translucent, allowing enough light to allow the growth of algae on the perlite inside.

We took the Dutch buckets out, they were an over complicated solution to a small problem.

Our friend Nick gave us three big plastic tubs and an IBC which we promptly chopped and flipped, converting the top onto a floating raft bed and a fenced off area for growing Azolla.

The old fish tank was reused in the front yard and the IBC became the new tank. We bought a 5000lph pump and used one of the new tubs for he sump. The flow was simplified using flexible grey hose (as recommended by Rob Grey) and the pipes to the various sections beds were split so we don’t use the single flow to fish tank idea and rely on siphoning and overflow. This allowed a lot more customization of flow.

We added 12m of PVC pipe beds that could now be operated with the new flow rates.

Over a few days, we noticed the sump was too small and the pump was running dry. We put up with this for a month or so before investing in 50 litre storage tub to add holding capacity. That was still too small, so we went to 75l. The story was still the same so we went to 100l. This was still running a little low for me, no backup in case things went a bit astray.

We decided to bite the bullet and but a 200l pond tub that gave us more than enough capacity when added to the existing sump. It was pricey but the only big tub we could find that had a low enough profile to fit under the media beds.

It’s all been running well for a cour of weeks now.

Here’s a brief video showing it all off…

Related Blog articles:

First steps

Ready for production

Second stage aquaponics

A new bed

Finally fish

Dec 2017 update

A new tank

Winter 2018 walkthrough

Summer October 2018