Backyard Aquaponics
A place to discuss aquaponics

Planted some pak choi, chard, turnips and cauliflower tonight, unfortunatly the parsley, chives, spring onions and some of the chard is'nt ready for transplanting. I should be able to transplant the rest in about 2 weeks.

Got a heating mat, 2 large air stones an some cichlid food today, hope this food is good enough, was the only food that I can find in my area exept koi food.

Planted some cherry tomato seeds last night and put seedling tray on heating mat.
Got a old 60liter aquarium today from a friend, so going to turn it into an indoor system and move my bergriver redfin to it. Will also move tilapia fingerlings to indoor system if they breed.

Did a water test again tonight, nitrates are down to 25ppm, also planted some lettuce seedlings that I got from local nursery.

Interested in that black pipe heater you have going there Jaco. Perhaps you need some kind of finer control of when the water is pumped to the pipe. Otherwise you risk cooling the water as well as heating it. Planning on doing the same thing but perhaps make a box with a polycarbonate cover for the pipe and use an arduino board to control the pump and monitor the temperature in the water and the greenhouse and the solar heater. Then only pump when it is hot enough in the solar heater, and stop when the water gets too hot.

I have one thing to say about your choice of fish. Even with passive solar heating which kept my water temps above 15 all winter, I still lost all my Tilapia to disease. There immune systems are just too compromised from being too cold too long. Why don't you get some trout for the winter? You could get a few fingerlings from Jonkershoek hatchery. Not sure if they would require you to provide a permit though.

For now all pumps are only running during the day and the solar heater never cooled the water very much on a cold day, the grow bed takes care of that. I'm in the process of coding an arduino to monitor ambient, solar heater output, FT temp (might add a light sensor too) and control pumping according to all parameters but coding was never one of my strong points, so it's going to take a while to get it running.

That's not very good news, hope mine survive the winter. I contacted the hachery in Jonkershoek and they sell a minimum of 10kg trout at a time, the only place I can find a lesser amount is in Montagu, it's going to cost way to much for the permit and fuel to be a viable option, will be much cheaper getting goldfish for AP and buying trout at woolworths.

Brian, how long was it before they started to die?

They survived for a long time...4 or 5 months... but they ate little to nothing and eventually started to die until I was getting one or two dead ones a day. Not 100% sure it was the cold but that's where my money would be. I think if you really focus on it and have your system in a greenhouse and have a solar heater, and everything properly controlled and insulated you could probably get tilapia to work this far south. But I'd get some trout asap if I was in your shoes. Or go with some koi. How big is that growbed of yours? You can probably only stock a couple of kilo's anyway and it may not be worth trying to raise fish for the plate. Given the mission involved in getting permits and transporting them etc etc..

I use to have blue tilapia in a 500cubic meter concrete dam in montagu that survived the winter, some days 5mm of the water was frozen and we had no deaths in years until we sold the farm. Think for now I'm going not going to add more fish and just hope for the best, i have 5 pseudobarbus burgi in there to keep the system going if the tilapia survive. The GB is 150L, too small, but I'm going to build a much bigger system soonish.

Will this type of AP system work with a small pump and an external swirl filter?

As long as the fish don't eat all of the roots.

Hi Jaco, I've been thinking of this one and what I don't see is a good substrate for the bacteria to grow to convert your ammonia to nitrates in the nitrogen cycle. That is why many people will add a DWC (Deep Water Culture) bed to their existing set up as they have existing grow beds which contain the useful bacteria to perform the necessary steps in the nitrogen cycle.

If you add this to an existing AP set up I think you will get good results but I don't know how well it will work on it's own.

This is just my idea and I might be completely off base so I would suggest you do a little more research. It might even be worth doing as a test system to see how it performs.

I also agree with Ron - it depends on the fish you're going to stock. If you have fish that love plants your roots are going to be clipped all the time limiting nutrient uptake by the plants.

Regards, Martin.

I've been doing lots of research on this topic and so far I can't find any evidence that it will or will not work, probably didn't search hard enough. Lots of people say that the bacterial growth on the sides of the tank, foam and on the roots is enough to keep everything going.
I would like to test it and see where the problems lie before I upscale the DWC in the future. I might even leave out the swirl filter and just use the aquarium filter I already have.
Originaly I wanted to put tilapia in but with some research I found out they eat roots, so now I'm going to move the pseudobarbus burgi over to the aquarium system, not sure if they would eat the roots, not much info on them available, all I know is that they are in the Cyprinidae family that contains the carp and minnows and that they only grow to about 11cm. They also don't eat very much and I only have 6 of them.

I think it's worth giving it a go to see what happens. It would be great to see your results.

I see the pseudobarbus burgi (Berg River Redfin) are an endangered species, do you need a permit to keep them?
https://en.wikipedia.org/wiki/Berg_River_Redfin

Regards, Martin.