Backyard Aquaponics
A place to discuss aquaponics

Hey Veeb:
Just wanted to mention you can have beds after as well as before your sump; like the ones before the sump would be nutrient and solids heavy and the ones after the sump would be "cleaner". I guess you could tailor what is planted relative to their nutrient needs, heavy feeders or ones that like all the gunk in the first and light feeders in the after sump. This assumes the ones after the sump have to be mounted higher than the tank for gravity return, which would probably be too high from your pictures.

Was talking about this last night re: my second system and came to the same conclusion. Less dependency on equal flow rates would be required hence much easier to set up once the autosyphon was mastered. The only thing that is stopping me doing it that way is that I would need a 3000 litre sump

Dave - you are correct, would be way too high. What I do intend to do though is have some beds that are fed directly from the sump, with drain back to the sump. by gravity feed. This will require another pump - but I'm happy to do this. Regarding nutrients, I agree that ones fed with water that has already gone through a bed will not have the gunk - but all previous testing done by the VI dudes and others suggests that there will be little drop in nitrate level through a single cycle through a bed - even a 30metre channel bed.

Stu - I think the word sump puts a negative slant on the idea (my dug in 'fish tank' will only be 2300 litres :-).). I do have some thoughts on how you might be able to reduce the size of the sump, will have a play when I get a chance and let you know the result.

A quick system update:

1. Autosyphon continues to operate without a hitch.

2. I have now installed the 100mm drain pipe around the 80mm pressure pipe stand pipe in the fish tank. This means that the solids are now gettign drawn from the bottom of the tank and out of the standpipe to the grow-bed. Tank is pretty clean - but I think if I extend the veturi pipe I will increase the whirlpool action lower in the tank and make sure all the solids go to the centre. I just need to get an appropriate size coupling and then I will do it.

3. I in planning stage to instal a 200 litre round poly tank to the side of my sump and run it as a DWC container. If this is effective I will add more.

Okay, I will be interested to hear your id3eas. I am just waiting on the price for my 5300 ltr system with 4 big growbeds, before I order anything I need to be sure of how the system is going to run

Stu - my idea was a lame one. Have worked through it in my head and realised it will not work.

My perch ate heaps this weekend. It is unfortunte that during the week I am never at home durign prime feeding time. Now they are in the bigger tank though and I am on the home straight to gettign them in the pan, I must make the effort to at least give them a feed in the morning before I leave for work.

As well as the usual pellets, green stuff and meally grubs that I give them as a treat - today I fed them quite a few African Black Beetle larvae. I always get heaps of these breaking down the stable manure I use in my conventional gardens and also the grass heaps (from mowing) that I let compost down. Looked like they loved them - and they had already had their pellet ration.

That damn beetle was the bane of my existance when I had my mowing round. You can water all you like, but the lawn still looks shit.

One thing I have noticed with the silvers, they are much more willing to have a go at different foods. I have found them, even at this early stage, to be a most interesting fish to keep.

At first I was a bit reluctant to feed them this larvae, because as you probably know the black stuff at the back of the animal is basically dirt - and pretty compacted at that. In the end I did it anyway - figured it will just add extra minerals to the system :-).

VB, I am sure you already know this, but watch out for the bacteria levels catching up if you all of a sudden increase feed rates. This week, I fed over 600 and up to 800 grams of food per day after normally feeding 400, and by the end of 5 days doing that, I had lots of fine solids in slightly murky water, and registered nitrites and ammonia. That was friday morning. I skipped one feed and only fed 200 grams friday night, and by saturday morning, the water was crystal clear and perfectly balance again. But if I continued to feed at the higher rate, I am sure i would have upset the system.

I think my system will handle it - but I will do some tests a bit later. One advantage of having the continuous running pump and the autosyphon is that my tank water gets turned over fairly regularly. Although my pump is pretty small in comparison to the mosters you use - I also have less water in my system (less than 1500 litres in total - including sump).

Will go and test now. Also wat to do a test on the water in a small duckweed pond I set up today. I filled it with water from my system and want to guage over a few days the drop in nitrate level.

I suspect by how my week panned out, that it takes about 4 to 5 days of extra heavy feeding to really make a difference. I have about 3000 litres of gravel, and it only took about 12 hours for the bacteria to catch up. I suspect you wouldn't register anything for at least a couple more days, but I would be interested for you to test on say Tuesday, if you continue to feed a lot more than usual. You are right though, My system only cycles 14 times a day with about 45 % water turned over during a cycle, so you would be far better off than me with more turnover if your feeding regime changes, as your bacteria get more of a chance to get to work as it all happens

I haven't worked it out exactly - but I reckon my water probably turns over a little under once an hour.

Famous last words. PH has dropped big time and I am registerring .5 for ammonia and nitrite . No more feed for now - will test in the morning and if need be, do a water change at that point. Have added some extra shell grit for buffering and also put a tiny bit of ph up in (fully aware that I don't want sudden fluctuation.

Shit, shit, shit, shit, shit - silly, silly boy.