Aquaponics Adventure Mark II part II

Aquaponics - 7 Comments » - Posted on March, 31, 2008 at 9:59 pm

This is a continuation of my Aquaponics photo-journal, part one is here.

This is the overflow from the main fish tank to the beds. Notice the pipe on the inside of the tank, this extends to the bottom and so when the tank “overflows” it’s actually sucking the crap (quite literally) off the bottom of the tank and dumping it on the beds. I’ve got a 50mm end cap with holes drilled in it on the end so no unsuspecting fish end up flapping about on some hot red rocks.

And of course the key ingredient to any Aquaponics system is fish. I had 70 goldfish (of various varieties) delivered last Friday.

I also re-plumbed the pump pipe to go through the side of the sump (instead of just sticking out under the lid). This allows me to put the lid on. The sock on the return pipe filters some of the dust and solids coming back from the beds.

My dog Archie usually jumps up on the sump and rolls over for a belly scratch, he came sprinting over whilst I was doing this work and my “Archie Nooooooooo!” fell on deaf ears as he leapt up onto the sump….except the lid wasn’t on….. and he plunged in and went straight under. He is the first living thing I’ve “harvested” from my aquaponics system.

I have run some black pipe from the outlets in the bed to the other end of the bed. My rationale here is that the solids coming out of the tank want to be as far away from the drain as possible. This means that the beds can do the best possible job of filtering out solids.

I used some old standpipe from system one to act as the last part of the pipe from the pump. Because it has holes in it, it creates a venturi effect which sucks air into the pipe before it goes below the surface of the water. This does some additional airation of the water, and stops the water siphoning back into the sump when the pump is turned off (by sucking in air and breaking the siphon effect). I plan on doing something a little less dodgy in the future.

I adjusted the standpipes so that they can handle more water by chopping off a whole side and making the holes down the bottom a little bigger. This increases the drain rate and means that it’s even harder to overflow. Note the adjustable “level control” implemented by the extra bit of PVC near the top.

This is then stuck in the beds, and has three states, empty (no photo), filling/draining (first photo), and overflowing (second photo).

The idea is that the water level rises to just underneath the gravel.

But doesn’t get too full. If the water rises above the gravel it gets direct sunlight which allows algae to grow. The idea is to keep the water out of the sun where possible. I still need some fiddling with my standpipes to get the level right.

The system works off a timer in my shed. Basically it’s a cheapo $2 Bunnings timer which turns the pump on for 15 minutes and then off for 45. I will need to run it like this for about a month for the system to “cycle”. A system is “cycled” once the bacteria needed to convert Ammonia to Nitrates has established itself. There are two types, one to convert Ammonia to Nitrites, and one to convert Nitrites to Nitrates. Once a system is “cycled”, Ammonia and Nitrites will be zero, and Nitrates will be present. At the moment, my bacteria aren’t established yet, and thus I have a ever so slight Ammonia reading!

Aquaponics Adventure Mark II

Aquaponics - 3 Comments » - Posted on March, 26, 2008 at 9:12 pm

Firstly, lets make sure you all know what aquaponics is all about. I won’t explain it well enough, so I’m not going to try. Lets just say it’s a cycle where fish and plants thrive in a symbiotic relationship where the fish provide the plants with fertaliser, and the plants clean the water for the fish. If you want to know more see these sites:

  • Joel Malcom has headed the craze in Aus and his site contains plenty of info as well as a lively forum. He also wrote a book for beginners which you can buy.
  • This free magazine is a great publication from the forum members at BackyardAquaponics, and a great intro to Aquaponics .
  • This page contains a pretty good summary of the process.
  • This guy seems to summarise the pros fairly well.

Little do you bloggers know, but my first Aquaponics adventure was a bit of a failed attempt. I think the main problem was that I was living in a rental, and thus I’d set it up at my parents house. This created all sorts of difficulties to do with maintenance and monitoring. It didn’t help that it was my first system and was flawed by design. Basically, if the power went out, the pump in my sump wouldn’t turn on and I’d lose about 500L of water into the neighbours yard. The fish were fine with this, but when I topped up my fish tank with water from the rainwater tanks, it changed pH, temperature, water hardness and all sorts of other parameters which the fish really struggled to deal with, and died.

So we bought a house and I’ve started setting up the Mark II system at my house. It’s what the BackyardAquaponics crew call a CHIFT PIST system – Constant Height In Fish Tank, Pump In Sump Tank. Basically the concept is that you have a large sump, in my case, 500L, which is the lowest point in the system (the sump) and houses a pump which pumps water up to the main fish tank. The main fish tank (in my case 1000L) overflows and the water runs out into the grow beds. These drain back to the sump, closing the loop. With this system, if the power ever cuts out, there is no circulation, but there is also no loss of water. So essentially it is more robust.

Here is a photo blog of my work in progress:

This is the site of the system, it’s behind the shed and that might throw up a few problems of it’s own (it might not get enough light) which I’ll have to deal with later:

Below we have some stills showing the back breaking work of digging the sump into the ground. This provides insulation and ensures that it is below the drains of the growbeds.

Below is the sump and fishtank in place. The sump is the green thing, the fishtank the black thing.

Then we have the growbeds. These bathtubs are filled with rocks which act as the biological filter for the system. In the photo below I show how I’ve raised them off the ground so that I get a height difference between the sump and the growbeds and also raise them up to a comfortable height to work with.

For draining the bathtubs I use a regular ol’ bathtub drain with the center thingo popped out.

Then a 40mm PVC adapter freakishly slots in that and makes a great seal.

And then my standpipe will fit into that (although this picture just shows some uncut 40mm pipe and the bathtub with some water in it – proof of concept though).

Put on the plumbers hat, plumb the overflow from the fish tank to the grow beds, and the drains from the growbeds to the sump. I use T’s in most places instead of elbows as it provides a “view port” into the plumbing and prevents any siphon effect from forming.

Then you have to wash the rocks to get all the dust and crap off them.

And you end up with two filled grow beds!

This is the reason you wash your rocks: GUNK. Look at this stuff, you really don’t want that in the bottom of your growbeds.

The concept behind a standpipe is that it sits inside the grow bed and drains at a steady rate. So when you have water coming into the beds at a greater rate than it is draining, the grow beds fill with water. When you turn off the water, the grow beds slowly drain. So that you don’t overflow the beds, you make it so that if the water ever gets above the level of the rocks, it just overflows into the standpipe and thus the growbeds can never overflow.

My standpipes have two small holes drilled in the bottom of the 40mm PVC pipe connector, and a large section cut out of the top with a PVC “C” to provide an adjustable overflow level control. In the photo below, the bottom of the standpipe is on the left, the top on the right. The bottom of the standpipe (left) slots in the drain of the bathtubs as seen above.

Now we don’t want the standpipes getting all clogged up, and we want to be able to remove them for maintenance. So we put in some 90mm PVC to protect it. We need to drill holes in this so that water actually comes through to the standpipe. Below is a picture of this 90mm PVC pipe sitting over the drain of the growbed without the standpipe in place (but that’s where it would go).

This is showing the water returning from the growbeds to the sump.

This is a work in progress, and as such there are still a LOT of things I need to do to get this system up and running. I’ve actually got a fair bit of it done and just not taken any photos, so we’ll see. I might just update this article, or I might post it in another. Either way, you’ll hear more about this aquaponics adventure in the next couple of weeks.