Theme changes, and commenting system changes

As you may have noticed, I've changed the theme, the old one was rather slow to load. Comments are of course, as always welcome. I have changed the commenting settings, to be more liberal, hopefully it should work (and not attract spammers)

Apologies for lack of updates, here's what you missed.

So we had a fairly eventful 2 weeks. Jared's left for Australia, so it is just me and Sam here at the moment. The original pump failed and couldn't be fixed. As it turns out, this is to be expected from running a bilge pump continuously. So me and Sam forked out  $140 for a submersible pump designed for continuous use. The peas have started to flower, and the plants in the grow bed have really taken off! A botched attempt to fix the sump tank necessitated a complete drainage and removal of it. It was rather tricky to find a suitable container large enough to hold the water needed to fit the water drained out of the grow bed as it cycles. Thankfully recycling had been through and as such the recycling bin was empty. Our use of the recycling bin is almost definitely against Christchurch City Council bylaws ;).

Sam attempting to fix the original pump

The state of the peas

The state of the lettuce

The state of the tomatoes

Attempting repairs on liner

The recycle bin being used temporarily as a sump tank while we fixed the liner

New domains, a new wiki, and a jammed pump

This morning when I checked the grow bed, I found the pump was not pumping! I disassembled the pump, and removed the blockage.

The blockage

By this time alas, the plants were looking pretty displeased by the situation.

Displeased plants

However, after restoring water supply, and flooding the bed by inhibiting the flushing mechanism, The plants appeared to come right.

Today I also set up the new aquaponics wiki (wiki.aquaponatronics.org) in order to document our efforts in more detail. At the same time I set up a slightly shorter domain for accessing this blog : blog.aquaponatronics.org .

PS:
If any of our lovely readers would like to edit or contribute to the wiki, send me an email at:
<my name>@ehmish.net

Fertiliser, pole patching and kelp

Results of dramatically increasing fertiliser dosage

One of the holes Jared patched failed, which Sam kindly repaired for us.

 Kelp me and Sam collected from the beach, we are exploring the option of using it for fish food.

Bed woes

After discovering a leak in our water tank, I decided to turn off the pump overnight in case it ran dry.

What we discovered in the morning after it rained:

Turns out it's a really bad idea to turn off the pump! All the plants were really limp. Thankfully most of the plants recovered, except for the basil.

While the tank is empty, here's a photo of the pump:

We fixed the leak and filled it back up, then replaced the siphon pipe which also had a leak. Now the system is running very smoothly!

Next we have to cycle the system to introduce the bacteria into the system. We will do this without the fish to start with, to ensure the system is stable before they are introduced.

To cycle the system, we add ammonia daily while constantly monitoring the ammonia, nitrite, and nitrate levels. As the bacteria grow, the ammonia levels will drop, and the nitrate levels will rise. At that point, we can introduce the fish and we will have a fully functioning system!

Rain, plumbing issues, and peas, Oh My!

So we had a few issues with our newly filled grow bed. The Bell Siphon valve jammed closed, which resulted in the bed almost overflowing. The valve triggered just in time (no pics alas). In a separate event, last Wednesday, we noticed the bottom tank was leaking, and in response we turned off the pump to avoid the pump running dry. The next morning we turned the pump back on, alarmed that the plants seemed to have suffered considerably overnight from the lack of water. The rain over that night seemed to have done practically nothing to help the plants, and may have even harmed them (see the picture below of the abrasion on the stem). To end this post on an up note, The peas we planted a few weeks ago seem to be doing fairly well!

Current state of the grow bed

These abrasions may be related to the rain we've been having lately

Surprisingly the wind hasn't damaged the peas

Sad tomatoes

Damp earth resulting from the slow leak in the bottom tank

A few videos from the last few days

Behold

Bell siphons are a marriage of witchcraft and plumbing.

It is possible that we need a larger fish tank.

Every day I'm gravellin' - camera ran out of power before capturing Hamish's brilliant wok-spade. 

Done! (Almost)

We finally have a working garden!

Planting things in gravel was a bit of a challenge, since the roots are very fragile, but hopefully they won't mind.

I added a 12V power supply to the electrical box. The pump runs really quiet, and has pretty decent flow. Soon I'll add some electronics to turn the pump off while the bed is draining, and to monitor water levels and temperature.

This is the siphon drain system. It's a bit hard to explain, but basically when  the water reaches the top of the black pipe, the water draining out pulls the water up from the bottom until the water level drops below the slits. The outer pipe below has holes drilled in the bottom, and the other pipe laying on its side is closed on the top.


The system fills up and drains automatically using this system, it takes about 15 minutes to drain. It's pretty cool what you can do with physics!

Here's my good friend Tim helping me fill the grow bed with gravel

Feel free to leave a comment if you have any questions :)
We live in Upper Riccarton, Christchurch if you want to come over and have a look.

We have to wait a few weeks before we fill the lower tank with fish, so stay tuned!

Gravel!

Today we got a trailer load of gravel to fill the grow bed up with:

After that we put the grow bed in its final location, and added the drain pipe

We put an old tarpaulin underneath the plastic to help stop the plastic from puncturing, and to support the gravel better.

The lining of the grow bed

Water Level Prototype

After doing a bit of research, I settled on a capacitive water level probe. It uses an insulated wire that dangles into the tank, which forms one plate of a capacitor. The water forms the other plate of the capacitor, so the capacitance will vary with water height.

The capacitance only varies by a few pF, but it is measurable! The trick is to measure the time it takes for the capacitor to discharge through a 1Mohm resistor:

Here's my prototype test circuit in action, it reads digital 20 for an empty tank, and 40 for about 30cm of water. I should be able to increase the accuracy beyond that.

Aquaponics is a method by which one can eat fish poo without becoming sick

Construction - Week 2

I got a waterproof box for the garden, which will contain the electronic monitoring system and ran some Ethernet UTP cable and a mains cable.

The frame will support the growing bed, which will contain gravel.

---

We also started construction of the grow bed

Grow bed construction

Jared standing on the grow bed in order to test it's strength

We're now starting on the grow bed. This will be where the plants will be growing, fed by the nutrients in the fish tank. Our estimates of the weight of the grow bed once full are around the 1 tonne range. Later we took the bed off the stands and back onto the ground where we're going to build up the walls and line it with HDPE ( the stuff we used the the tank) to waterproof it.

Fish Tank 1.0

Our first attempt at a fish tank failed miserably

Construction - Week 1

We found the perfect place for the fish tank, it's an old coal bunker that was filled with dirt.

After digging it out and finding a whole buckets worth of bones (!!!) we lined it with HDPE plastic sheeting and anchored it with a wooden frame.

On our first fill up, we encountered a problem; the hole in the bottom right corner was bulging, and as we tried to fix it, we punctured it and had to empty it (see Hamish's video in an earlier blog post).

Once it was empty, we patched it with duct tape and refilled it.

Here's the fish tank after properly filling, with a wire mesh screen to keep the cats out:

Introduction

Welcome!

This blog is here to document our progress of an aquaponics setup. Aquaponics is similar to Hydroponics, except instead of using chemicals to feed the plants, the natural bacteria in the system break down fish poo into nutrients for the plants.

In addition, I'll be adding an electronic monitoring system that monitors the garden's health, as a side project.

All our efforts will be documented here.

Members:
Hamish Farrant
Sam Fursdon
Jared Sanson