Havemore Happenings – 23 June 2019

iAVs/DWC Comparison

This week, saw work begin on the sand biofilter for the iAVS…and the DWC grow tank.  

Since Havemore Farm is a constantly changing feast, my first task was to clear the site that I had allocated to the grow bed/tank.  My NFT system – and a couple of shallow beds – were making temporary use of the space…so they needed to be moved.


The NFT was easy.  I simply created a new base for it – using cement blocks – and moved it across to its new temporary location.


The shallow gravel beds required a lot more effort…including the removal of 600kg of gravel.  Having seen almost as many incarnations as the Buddha, they are now stacked up – over behind the pond – awaiting their next deployment.


Given that the new bed/tank will weigh around 1.4 and 1.0 metric tonnes respectively…and my particular circumstances are such that they need to be above-ground, they are of robust construction.  I used cement blocks for the supports…and treated pine sleepers and formply…for the grow beds.  

I began to dig the holes for the sump tanks and it wasn’t long before Fate rolled up to the party…revealing some sewage plumbing right where I wanted to put the first sump tank…and forcing a change of direction for both me – and the sump tanks.

New Worm Farm

I already have a worm farm, but it’s in a repurposed ebb and flow grow bed – and I can make better use of it in that role.  


I own three mega bins…750-litre HDPE produce bins.  I’ve used them for all manner of things…often as fish or water storage tanks. Anyway, one of the bins has developed a leak, so its tank days are over…but it is adequate for use as a worm farm.

Organic Hydro Biofilter/Brewer

It’s been an interesting week following the startup of this little unit.  Follow my meanderings…HERE.

Getting the Right Perspective


The first photo shows the RAS, the iAVs and DWC beds with the duckweed pond in the foreground.  The second image shows the opposite view – from the pond back to the chicken house and soil pit.


Havemore Happenings – 16 June 2019

The Bloody Chickens

Egg production has been a real issue in recent months.  It’s been up and down like a honeymooner’s pants.  I’ve tried all manner of things to fix it…but I’m often my own worst enemy when it comes to dealing with problems like this.  Process improvement requires that you change only one variable at a time…otherwise you’ll struggle to know which variable brought about the improvement…but I’m sometimes too clever for that.  

This week, I finally cracked the code.  So, if you keep chickens and you want to know what the issue was, see HERE.

Organic Hydro Biofilter/Brewer

It’s been an interesting few days in my quest to understand more about organic hydroponics in general…and human urine in particular.  Follow my daily progress…HERE.

iAVs/DWC Comparison

I’ve set up the fish side of the proposed comparison. 

This unit is my microFish Farm 2.0…a stand-alone recirculating aquaculture system.  It comprises a 1,000-litre fish tank, two radial flow filters, a packed media filter and a moving bed biofilter.  This will be attached to a 1,000 DWC grow tank.

This is the fish side for the iAVs…and it will be attached to a 1,000-litre sand biofilter/grow bed.

Since this project is a comparison of DWC with iAVs, it’s probably useful to make the point, at this stage, that DWC requires more equipment than iAVs…so capital expenditure will be higher.  In this particular case, the cost is over double that of the iAVs.

My Workshop

My workshop often takes on the appearance of an exploded goat (shit everywhere)…but, this week, my minimalist self got in and de-cluttered it.  The workshop space is only 6 metres by 4 metres – and it has to perform a variety of function…including building food production systems, making and mending and tool/equipment storage.  Suffice to say, compromises are necessary.


Betting that it will stay as clean and tidy as it is now, won’t get you big odds at your online betting shop.  C’est la vie!


Havemore Happenings – 9 June 2019

iAVs/DWC Comparison

Inspired by a study undertaken at the American University in Cairo, I’m preparing for my own iAVs/DWC comparison.

The obvious question that arises is..”If the AUC already did such a comparison, what’s the point of repeating it?”  The answer is simple.  While the AUC study found that iAVs was the better method for Egypt, the methodology was flawed to the point where neither system was able to perform as it should.

The project requires that I build two systems – side-by-side – so that they are, as near as practically possible, operating in the same environmental conditions.

The fish tanks have a capacity of 1,000 litres.  The DWC grow tank also has a capacity of 1,000 litres.  The sand biofilter will contain around one cubic metre of sand…equal to a 1,000 litres in volume terms.  Each of the filtration modules is 200 litres.

With the iAVs, all of the fish wastes will go to the sand biofilter.  In the DWC, all fish wastes will flow through the filtration modules with a view to capturing them, processing them (out of the water flowpath) and returning them to the system – less the sludge.

I’m currently gathering the hardware to build these systems and I hope to commence their construction in the coming week.

Organic Hydroponics

A few weeks ago, I built a little biofilter/brewer to enable me to learn more about cost-effectively turning organic substances into plant-available nutrients.    

The biofilter consists of a 20-litre plastic drum into which I’ve placed a 750-litre/hr pond pump.

The 20-litre bucket is fitted with a lid into which I’ve drilled some small holes.  A 10-litre bucket sits on top of the 20-litre drum – supported by the lid with the holes.  I’ve placed a coir garden pot liner inside of the 10-litre…and part-filled it with coarse sand.

The sand will filter out any solid materials and will serve as bio-media…housing the nitrifying bacteria and other microbes that will convert the organic substances that I want to decompose so that they become plant-available.

The simple plumbing arrangement allows me to adjust the rate of flow through the top bucket while also stirring – and aerating – the contents of the 20-litre bucket.

I’ve just started it up and my first trial will involve one of the most accessible organic substances of all – human urine.  

Notwithstanding, it’s alleged ‘yuk’ factor, urine is very interesting stuff.  It contains valuable nutrients which are wasted by flushing it down the toilet.  But its role in the waste cycle doesn’t end there.  We waste millions of megalitres of potable water – using billions of dollars of infrastructure – flushing it into waterways where it (along with the other substances in wastewater) harms the aquatic and marine environments.

Stick with me – and we’ll both learn more about making – and using – ‘pee tea’ from urine.


Havemore Happenings – 2 June 2019

My love affair with my new BlueLab Truncheon continues unabated.  I always knew that hydroponics, at the backyard level, was able to produce clean fresh food…quickly!  I never realised, however, that it could be made so easy.  Ensuring that my hydroponics plants are receiving the nutrients that they need, is as simple as filling up the water reservoir – and adding nutrients.  The Truncheon then indicates when the nutrients at the correct level.


I’m busy putting all of the hardware together for a deep water culture (DWC) unit…and my first iAVs system. I’m planning to undertake a  comparison of the two systems.  The grow tank for the DWC…and the sand biofilter/growbed for the iAVs…will be made of treated pine sleepers and will be lined with low-density polyethylene liners.    I had planned to put the fish tanks in-ground but I have a complete 1000-litre recirculating system…and a spare 1000-litre tank…that I have lying around.  Not only will it save money but it will save time, too.


In case you were wondering, the little box arrangement above the moving bed biofilter (in the photo above) is a native bee hive – a very expensive way to provide a living space for native stingless bees.

This week, we’re planting out kale seedlings…and harvesting some lovely pak choi.

Take it easy…and I’ll see you next week.


Havemore Happenings – 26 May 2019

My hydroponics systems are producing at a satisfying level but, it’s time to ramp things up a bit, so I’ve invested in a Bluelab Truncheon…and a pH tester. 

The Truncheon measures nutrient strength…and the pH tester (not surprisingly) measures the pH of the nutrient solution…and it’s the pH that determines nutrient availability to the plants.  

The Truncheon got its first workout earlier this week. It showed that the nutrient level in the seedling propagator was inside the recommended range but that the level for the NFT and gravel systems were on the lower limit. Based on this information, I added more nutrient to the reservoir.  I love this device already.

Food production got off to a slow start this year but I resolved to make it the main priority – and we’re at full throttle currently.  We’ve got 72 NFT holes filled with pak choi, silverbeet and a few strawberry runners.  Another 4m2 of hydroponic grow beds is full of kangkong and silverbeet – and another 30m2 of wicking beds are growing pak choi, silverbeet, Russian comfrey, pinto peanut and a mix of edible herbs.

I receive frequent questions about iAVs’ performance around things like annual fish production, plant spacings, water use efficiency and the relationship between fish feed and plant production.  While I can recall most of the key numbers, I’m always a bit hesitant to quote them off the top of my head – so I’m inclined to want to check them for accuracy before committing myself.  The problem with this is that the metrics are spread throughout several documents – and finding them can burn up some time.

To make the task easier, I’ve put them all together in a single document.  There are others that are still awaiting discovery among Mark’s responses to various blog comments and they’ll be added as they come to hand.

One of the things, about which I’ve wondered, is why people are so attracted to aquaponics.  I don’t mean the often quoted benefits – like reduced water use, faster plant growth and the non-use of chemical herbicides and pesticides.  They’re frequently cited by newcomers to the discipline, but they’re generally a rationale rather than the key attraction.  Anyway, I wrote a very brief article on what I think attracts people to aquaponics.

I’ve just discovered ‘food swap meets’…local gatherings where people who grow food swap their surplus with other growers for food items that they don’t have.  Great idea!


Havemore Happenings – 19 May 2019

We’re getting rain on a daily basis and our water tanks (10,000 litres capacity) are full.  I have another 6,000 litres of temporary storage deployed, too.  In addition to storing water, these ponds, tanks and tubs are also used to grow duckweed.

The hydroponics systems – NFT and gravel media beds – are going well.  I’m growing kangkong in the gravel beds – for the chickens and it’s a winner.  It grows quickly and it’s a quality greenfeed…and great for stir-fried dishes, too.

Most of the wicking beds are planted out to vegetables like pak choi and silverbeet (Swiss chard).  At the moment, my focus is on fast-growing plants for food and fodder.

Our little ebb and flow seed propagator continues to exceed my expectations.  I’m currently using it to grow kale seedlings.

The chickens have settled down and are finally laying enough eggs to meet our needs…still with scope for improvement.  I’m now able to feed BSF larvae and homegrown green feed (in addition to their organic base ration and kitchen scraps) on a daily basis.  Although I provide the organic ration on an ad lib basis, my goal is to reduce their consumption of it (it’s expensive) by supplementing with homegrown ingredients.

The big win, this week, was the arrival of a bulk-a-bag of sand (made from recycled glass).  A gift from an old friend, the glass sand will be used to build my first iAVs system.