Backyard Aquaponics
A place to discuss aquaponics

My Silver Perch system has about 25kg of fish biomass... 1000L tank, and 1200L of growbeds...

My little blue barrel system... 800L tank & 400L growbeds.... was originally powered by yabbies.. and is consistantly understocked.... but probably consistantly out performs the bigger system....

Hey hydrophilia,
it's not a problem for me to understand what you're writing, but i think it's difficult to understand what the dom is writing :-)
What do you mean with urea, you're not meaning the human urea don't you ?

Ok i've 25 5cm Tilapia fingerlings in my aquarium for the garden.
The grow very fast, and i think i'll try only this 25 fishes.
How often do you test the water of ammonia, nitrit and nitrat ?
I think only no² and no³ is enough when the systems cycle.

Unfortunately, you don't be able to use Tilapia, cause i've about 200 frys.
But i think it's also expensive to send it.


Dom

urea fertilizer like this: http://www.google.com/products?q=Espoma ... =en&tab=wf


When I have a large change (if I have added fish to a system or if fish are dying) I check ammonia and NO2. At first I check every day until I can predict what will happen, then I check every two or three days to make sure things are ok for the fish.
I only care about NO3 for the plants, so I don't test for that often at all.


Yes. I've tried tilapia, but it is too hard to keep the water warm enough. I still have two in my house aquarium, but none outside.

So which kind of fish do you use?
Will they grow although fast as tilapia?
I think in my littlegreenhouse, it will be possible.

You have a great edge, because you can by easy fingerlings.
Here i can easy get trout and carp.
But for my greenhouse (summer gets 45 celcius) it will be to hot for trouts, and carp grow very slow so i must leave it outdoor in winter.

Can you tell me a fish, which i can breed in tank, grow quickly, taste fine and survive temperatures below 10 degree celcius but also above 25 degree?


Dom

I use Silver Perch and Trout...

You should be able to do Trout through your winter.... but I'm not sure that Tilapia would survive winter.... or that they'd grow fast enough during the summer to get to plate size...

I'll let our American friends comment on Tilapia growth rates...



... if you find one... please let us all know....

Tilapia are mouth brooders... and will breed in a tank... grass carp may....

We seem to have a split conversation.....




Probably faster unless you have your water at 30degC. Tilapia do not seem to do well if temperatures are a little low.


Sorry. No such fish that I've seen unless it is catfish and they may or may not breed. It is supposed to be rare in aquariums and they do not breed until 2 or 3 years old.

If I were you I would get carp in spring and trout in fall. Carp should be large enough to survive with trout by then, I hope. Try it!

Rainbow trout grow fastest: I'm already harvesting 400gram trout (and one 490gram). The largest one was from a 200liter aquarium in my kitchen!

Thanks for your helpfulness, since i changed the manuel watering times to automatic every 2 hours for 15 minutes, it seems that the plants starts growing.

The underside of the leaves get purple, is this normal or to much nitrogen in the water?

Last year i also search in some boards after catfish and breeding in aquariums.
But i don't find anything, but i think its possible when i leave they in the system over winter, they like the cold temperatur for their sexual behavior.
In the wide nature, they has also a cold timeperiod, or?


Dom

That is a classic symptom of phosphorous deficiency. I would probably add some phosphate rock powder if I wanted to be safe or some phosphoric acid (VERY carefully so as not to kill fish with PH changes!) if I wanted fast results, but I really have no idea what is best or what is available to you...

Tomatoes seem to be really greedy in using up nutrients, but it is worth it: one vine I grew last year reached over 3 meters (even with me hacking it back often) and produced at least 25 kg of fruit (probably more than 50kg, but I was on a trip and others harvested for two months).

Is it not possible to add only iron and get the rest by the fish waste???

Theoretically, yes. However, when a system is new the solids contain much of the nutrients and it takes time (or worms) for these to become available. Also, some different plants have different needs: farmers will alternate corn and other crops since corn depletes N while leaving some other essential nutrients. Tomatoes seem to need lots of potassium. I try to balance nutrients by subtraction: I plant a lot of different seeds and seedlings and whichever needs the nutrients I have in excess and does not need what is lacking will grow best. As a system matures it becomes much easier to keep nutrients available.

Absolutely... if you're feeding your fish a commercial pellet feed... which has trace elements included (and phosphorus)... otherwise you might need to top-up and foliar feed some liquid seaweed... such as Seasol.. or more likely in your area... Maxicrop....

If you're suffering iron lockout due to pH ... then you're possibly locking out phosphorus as well...

But your system will mature, and with the help of worms breaking down solids... will gradually build the trace element availability within your growbeds..

Edited : Great minds think alike Hydro...

Hello friends,

thanks for your tipp with the watering.
They grow fine, i've add a pictures below.
And yes i'm feeding trout peletts with a low fat content.

I've ordered 10 brown catfish for next monday.
The price is not so cheap as at your location, for each i pay 2,50€.
I think they will be the best fish for my german weather.
In spring cold, in summer hot (30-35°C) and winter not so hard.

They survive temps from 4-30°C.

The catfish sound ideal if they can handle temperatures like that....

Today i've tested my greenhouse aquaponic system.
It consists of a fishtank 250x60x67cm and i planned two growbeds with 250x60x35cm.
At first i only use one of the growbeds.
So i see that my 1700L/h pump needs 9 minutes to flood the growbed.
And at the moment when the water begins to overflow in the pipe, i lost 11cm out of the fishtank.

So please explain me, how should i use 2 of the growbeds when the tank is only half full of water at the floodtime ?
Or is the ration not 1:1 or better 1:2 fishtank to growbed ?
When i take a look at some member systems, it seems that they all use less medium than fishtankwater.


Dom

Did you flood your growbed without any media in it??.... if so, you'll find that once the media is in place it will take up at least 50-60% of the growbed volume... lessening your "flood" volume...

Most people use either a sump, with a float activated pump returning to the fish tank... and/or a "Chift Pist" arrangement.... to resolve the problem of tank drain down...

Ratio is definitely 1:1 minimum.... preferably 2:1 IMO...