Backyard Aquaponics
A place to discuss aquaponics

Ok.. I got the overflow pipes installed from the FT to GB's and Filled the fish tank with water. Really exciting The overflows worked great but I could have made the FT level a bit higher. Oh well, no changing it now. There is about 120mm of tank wasted at the top. I will calculate the exact volume of water and see if the fourth growbed can be used for duckweed. Sadly this morning when I went to check the water level it had dropped 250mm so the tank is leaking . So it was out with the water again and yet another 5 litres of bitumin will need to be poured around the expansion joint between the wall and floor. That is where the leak is. I think we did not seal it up with enough gunk around there. I will do all the growbeds more around there as well. Will need to move some gravel around . Today in my meanderings around the local village I goy chatting to someone and they told me that there was a chap farming telapia in the village. I went around there but he was not there but I could see the now ex farm. The neighbour told me that it was the breeding farm for a large aquaculture farm on the local river called the berg river, where river water was diverted into massive dams where the fish where fattened. Aparently the project was halted by the food safety board as the river was supposedly polluted by an informal settlement upstream and the fish deemed unsaleable. This is irratating as that was where I was going to trap my stock. Now am not too sure.

Brian,

Just enjoyed reading through your thread. Nice work you do!! Looking forward to seeing it cycled and growing.

CB

Dang, leaks are frustrating. Good luck.



If you are getting them for breeding stock or netting tiny fry they should be fine. If the problem is bacterial or viral I would think that a couple months in your system would be fine even for larger fish. The only thing I would really worry about would be getting medium fish that have built up some mercury or other toxic load.

Note: this is based on reason rather than any evidence I have. *grin*

The system is RUNNING! well it was... I was playing around with the timer trying to get the flood and drain cycles working and then left to go out forgetting to take the timer in, and as there was no housing for it, and it rained the timer is now buggered as it got soaked and sand spattered all over it. On the bright side it was cheap and another one is being purchased for me by my wife as I write this. I was running it on half an hour pump time and 1 hour drain. The timer works in 15 minute sections and 15 min was not quite enough for all the beds to fill right up so I had to go with 30 mins. I must take back what i said about the overflow being to low as the pump I got is a .25Kw swimming pool pump and it delivers allot of water! The tank actually gets very close to the top during the pump cycle. the other problem was that the water all ran out of the pump into the sump when the pump switched off so it was not primed for the next cycle. I have put in a brass check valve to rectify this but I am a bit concerned about the use of brass in the system. Is this a problem? It is the only check valve I could find. I still need to finish filling the third growbed with stone. It is about half full now. The fourth bed I am going to try and grow both duckweed and watercress as well as some bullrushes and water reeds. I figure this will help keep nitrates stable while edible crops come and go. I have closed the flood to this tank right down so water only trickles in.

On the subject of flood and drain cycles.. what is a good cycle to aim for. Would a half an hour fill and a hour drain be good or would you want a longer drain?

The other issue I am having is that not having a greenhouse over the system and heading into winter the water is now very cold. Have not actually taken the temps yet but I am going to do that now. I am thinking that for cycling the system and for the first couple of months I am going to bung carp in the system. They will cope with the cold and it won't be too much of an expense if they become floaters as they are a free resource. I will then remove them in 4 months time and get the tilapia. I hear carp are really nasty to eat. Has anyone tried? There are plenty of recipes on the net for them and being the most cultured fish in the world, it can't be too bad. I was thinking to go with trout, but I don't think there will be enough time for them to grow enough in four or five months. How long does it take to grow a trout to plate size? I am also wondering how many fish I should put in. The tank being about 3800 liters. I must actually calculate the exact capacities of all the elements. It is raining like hell here at the moment so it is a bit frustrating as I want to work on the system.

I have a great new camera canon 450d so I am going to go and take some shots of the system and post soon

Another thing... I want to start cycling the system now and would like to plant the beds out. What can I dump in the water to get the nutrients up for the plants. I think we get a kind of seagrow stuff here made from seaweed. Anything to avoid in any potential products. Should I be peeing in the water and getting all other willing individuals to join me? Where on the forum is the best place to read up on starting the cycling?

Most people will recomend aged humonia (pee in a bottle and let it sit a couple weeks), but I just peed in my sump as I washed gravel and drank beer. Get your test kit now and test after everytime you add humonia to it. I did not and just peed in it for afew days and when I got around to testing the amonia reading was VERY high. Lookup "fishless cycling" in the search. For me cycling went really fast once it started.

Yes Deja... I need that test kit NOW! Here are some pics. And easy on the pee for starters...

Hi Brian,

I finally got back to your thread after being an avid reader for the first few pages.

Did you end up happy with your stand pipe choice? I did have an idea for an external stand pipe, but it might have been a bit fitting intensive and your set up is probably pretty permanent so I wont stress you with an idea of such genius that you wished I'd been reading your thread all along .


Your pump is higher than your sump. Pumps don't lift as well as they push water. Most people seem to be using sump pumps or you could put your pump in a hole ( a old 44 drum might make a good sump for it ) but if you get 90mm of rain in a shot ( that would deadset wash us away here ) you'd have to keep the water out.

Dex.

Hi Dexter. The stand pipes work well. Simple and efficient for now. I do worry a bit about the pipes blocking in the longer term but I have compressed air to blast through them if need be. . The pump works just fine with the one way valve in, it is just having the single brass fitting in the system that is a bit worrying. I went and visited the legend in Knysna Synaptoman and I am sure I remember seeing a brass check valve in his system so I guess it is fine. The System is now plugged in and running at 14 flood and drain cycles in a 24 hour period. Tomorrow I am going fishing!

Ok Dexter. Just fill us in on the genius idea will you! I can't take it no more!

Hey - Brian. Do you have shade up over the system yet? I took my time putting up shade and the water went from slightly green to pea soup in a matter of a day. By the time I got the shade up it was too late and while it is clearing, I still cannot see the fish all that well. Event a temp tarp over the sump and tank held in place by bricks would be good enough until you get something more permanent.

Most folks like to have a submersible pump in the sump or have the pump below the water level of the sump. The check valve will work, but I prefer to trust gravity: it never malfunctions.
A small amt of brass should be OK, but none is even better. I'm not sure at what point of the graph of surface area of brass, PH of water, temperature, salt, and water retention time the dissolved metal becomes a problem. I prefer to avoid it and use stainless or plastic fittings.


I wouldn't worry about 'ate stability as tilapia and carp are generally happy even above 500ppm nitrate. I've found it much more likely that the nutrients run low. But duckweed is always good for feeding to tilapia..


Depends on how fast the growbed is mostly drained and the number of fish. If your fish are very lightly stocked you might have a 2hr total cycle; if heavily stocked you would want a shorter cycle to maintain wtr quality. I have 2 beds on autosiphons that run about 10 minutes per cycle, but the beds are small and trout need good water. How long do your beds take to drain? An hour total cycle is generally popular...


Lots of folks eat carp, but they need to be held in clean water for a week or so to become better flavored. In an AP system that should not be a problem.


I think you can get about 2 or 3cm of growth per month...


You can try fishless cycling with humonia or urea, but that is dangerous if you have fish in there. With your volumes you might be able to continue adding humonia as a nutrient even with fish. I don't have time to run numbers now, but fresh humonia is urea which is a slow release ammonia source. It may, however, contain some bacteria.
I'm not sure I would want my friends contributing...I don't know where they've been...

I'm just working out how to do a drawing. Be prepared to be amazed..... or terribly disappointed .

I would have liked to get a sump pump bur they where much more expensive than the small swimming pool pump. The main enemy to the check valve would be debris getting lodged in it so I will fit a sieve filter to the end of the pipe in the sump. the check valve is not actually in the water so it is only the small surface area of brass inside the valve that is contacting the water.

Here are some action pics...

I have a bottle of 'supa natural' fish emulsion based fertilizer here. Says derived from fish and completely natural organic fertilizer. Can I bung it in for some nutrients for the plants?