Backyard Aquaponics
A place to discuss aquaponics

Hi All.
I'm new to these forums. So I thought I would post a quick overview of my first system. This is mostly been setup as a "proof of concept", being controlled by the PLC. The concept of this system could easily be applied to a much larger system.
The system is currently cycling at the moment with 5 comet Goldfish. This system will be run on goldfish for its entirety.
System consists of two 8 pot flood and drain tubes.
One 150L Fish tank.
One 50L Sump Tank. (this needed to be done as the fall of the drains were lower than the top of the fish tank).
Two 720L/hr pumps. One in the sump tank one in the fish tank.
One 6 input 4 output programmable logic controller.
There is a one low and one high float switch in the sump tank controlling the emptying and filling of the sump tank into the fish tank.
The grow beds are currently flooded for 15 min and drained for 15min. This may change after the system is cycled.
As this system is installed in my conservatory it gets quite hot so I have a thermostat controlling a large fan for airflow and cooling.
I have the API freshwater master test kit. Ammonia is just starting to show after 5 days. Feeding the fish twice a day.

This is the overview of the whole system


Here are the fish happy as ever


Cos lettuces doing well so far


Thermostat


The control panel with PLC power supply and mains switching relays.


I have lots more photos and info. Plus lots of questions but that will do for now. Any comments or advice would be greatly appreciated.

Welcome to the forum, the system looks really good.

A few comments..

First would be on your lighting. I dont know anything about what is required but I think you need certain type of bulb. Hopefull someone with experience will chime in.

If you havnt already, get some koi pellets for your goldies as the standard flakes dont have the goodies in it to assist your system and plant growth.

Also add some seasol or maxicrop to assist your plants until a nitrate colony is established.

I never had much luck with plain fluros...

But then I never had much luck inside at all...

Sent from my GT-I9300 using Tapatalk 2

Hi Thanks for the comments guys. Anything anyone offers is greatly appreciated.
Yeah the flouros are mostly to supplement the natural light in the conservatory. This system was previously a hydroponic system that grew tomatoes and peppers with some success.
But I was for more drawn to the natural balance that Aquaponics offers. I just don't want to spend a lot on any HPS or Metal Halide lamps for this little system.

Plus the flouros are cheap to run at 120W.

Yes I have heard of supplementing with seasol. I will see how the plants do till the system is cycled.

Any idea how high my ammonia is likely to get before I start seeing Nitrites?...
My Ammonia has been stable at 0.25 for a few days now.

El D, I'm curious about your high/low float control. Been looking for one myself for a few weeks now with no real luck. Currently trying to run my pump on a piggyback float and it seems like it's creating more problems than it's worth...

Granted, half a world away but maybe I can luck out and match something up somewhere....


If/when it comes time to replace lights, you may want to consider playing with LEDs. Probably all of a couple of hundred bucks US to build a small light that would cover everything you've got there, you could dial in your light spectrum more closely and would eat less energy. http://www.ledgroupbuy.com/ These guys have some fairly sexy heat sinks available by the foot that seem like they'd get the job done...

Hi FishB.

These are the Float switches im using.
http://www.jaycar.co.nz/productView.asp?ID=SF0920&keywords=float+switch&form=KEYWORD


They are currently switching 24V that is a digital input to the PLC. I don't know if you know much about digital electronics but high float latches the output connected to the sump pump high. And the low float resets the latch and the pump turns off. Very simple.

Hope this helps.

Ahhhhhh....Gotcha... I forgot about the PLC... That's a small luxury that I don't have at the moment.... I've actually been wondering if/how I could go about incorporating high low switches fairly inexpensively. I had actually tripped over a dual high/low float on a single pole a month or so ago and, of course, didn't bookmark it....

Yeah in order to do what i'm doing without some kind of digital logic circuit would be difficult. You'd have to run the pump through some kind of latching relay circuit. Or do some kind of wiring where the high float energizes a relay coil and closes the contact to your pump, but also have the low float in the same line so it would de-energize the relay opening the contact...It can be done conventionally but becomes a bit more of a headache..

So system is cycling right now.. has been 1 week. ammonia is not rising above 0.25ppm. do I just need to be patient of add more fish.????

Patience is your best bet Elldizzle. Especially when you have fish in your system

Yeah that was my thought. Its always good to get a second opinion from those in the know though..Thanks. Will keep everyone posted how I get on..

I had a system on a bore tank that had an arrangement of a float on a wire, with a sinker on the end, and some stoppers on the wire.

The wire went up to something similar to a counterweighted toggle switch.

So basically you adjust the stoppers, and the system would turn on the pump when the water got too low (switch supporting the weight of the float plus the sinker) and then turn the pump off when the water got too high (the float took the weight of the sinker).

It worked quite well, no latching special electronics, all done mechanically. The critical part when you're designing something like this is to make the float heavy so it will pull the switch down when the water level gets too low, but buoyant enough to be able to push the switch up when the level gets too high.

Oh well there you go. Just a bit of mechanics aye. I am in the automation industry so i automatically think digitally..

4000k or over on the tubes, or cool white, I would put some decent reflectors on those and get them a bit closer.

Hello Elldizzle; you have created a very neat and high tech system, so well done! I have a few comments.

The fluoro tubes that I used decades ago for my aqauria were special ones (Grolux, I think) that gave off a pinkish light to promote plant growth. I assume this same sort of light would be used for hydroponics so yours may already be of this type, since you say they have been recycled from a HP system, but it may be worth checking that your tubes are fit for purpose.

Your slatted wooden cover to your fish tank is basically a good idea but your comets could still quite easily jump through a gap and die from carpet burns.

Finally, the timber from which your fish tank cover is made appears to be treated pine. Whilst the formula for pine treatment has changed over the years and arsenic is now generally excluded, the other stuff used I believe is still not particularly conducive to fish nor human health. You might consider replacing the cover with a more inert and harmless material (with smaller gaps).

Best of luck.