Backyard Aquaponics
A place to discuss aquaponics

of all the "limes" its probably the safest.

There is a real pit fall in using the word LIME, wikki it!

it is used interchangably for dolomite, hydrated lime slaked lime, burnt lime. can't remember which but one of them is CaO, very caustic!

Just had a big storm in Brissy and my tank got an extra 500litre and nearly spilled over. I removed the pipe from the roof gutter. Don't need any more for a while

Week 3 of fish:

The Jades now range in size from 40-70mm (from 30mm).
pH is around 6.3 and I am Slowly adding dolomite to get it up to about 7.5.

The signs of Ich have completely disappeared. Don't know why but that's great.

The veggies are taking off and I need more growbeds urgently!.

Here's some pic's. You can just see a comet trying to get a look-in at the pellets (grains really). Grainy picture - sorry.

Cheers
Jamie

Veggeis after 3 weeks of fish

Veggies after 3 weeks of fish.

Hi Jamie,

Your grow bed is looking good. Mine is at a similar stage of development.



It's interesting that you make this post. During some recent rain, I stood watching the trickling drain pipe on my growing system and it occurred to me that rainwater could flood a system if there was enough of it.

Although you had your downpipe connected to your tank (rather than just your grow bed drain), you've clearly answered the question.

It's good to see that I've got a near neighbour.

Gary

Jamie, you are going great, the fish look big, fat. More growbeds! the pressure is on!

Hi Gary.
Didn't click Bundamba was a close suburb - thought it was up north somewhere.
I have just been checking out your system - Great read
It's fascinating how everyone is doing something different and getting good results. This site is like a giant lab with lots of people coming up with great ideas. I love it

yeh Monya - Just bought another bath.
Then I have run out of space for gravity feed return to the pool.
So I'll have to get a sump pump for the additional beds.

I have got to find more efficient growbeds than baths!
I think I'll have to try this coco coire stuff as a medium and lots and lots of cheapo plastic containers from B's. The only thing that doesn't appeal is the mass of extra plumbing I'll need having lots of small growbeds.

From what VB says - he's got 30 fish and his 550 litre growbed just copes -
I need at least 3,500 litres of growbeds.
Which is way too much gravel to stuff around with and 21 baths

I need to find some nice cheap plastic growbeds suitable for coco coir - in Brisbane. Any Ideas


Cheers
jamie

Aquaddict I see you suggest 1kg fish to 50litres growbed?
So 200Kg fish (I'm hopeful ) is 10,000 litres growbed
I can go into market gardening
That's 20 Murray growbeds!

Is something wrong here?

Mate it is all academic really. Fact is the way many systems will be run there will be small and more mature fish all being kept in some way shape or form to ensure continuity of supply. Therefore if one wants to grow out 200 fish a year, it is unlikely that one would have 200 full grown ones at a time.

There are a lot of variables that need ot be considerred when dealing with how much plant area you need for a given quantity of fish. These include the plant density, waht you are growing (some things take more nutes than others) and the time of year (some plants will grow quicker at certain times of year).

A lot of us here prefer to talk about feed to grow-bed ratio. Can't give you a number, but the point is you would only feed your fish the quantity of food that produces the amount of poo and other excretions that your system can handle. Obviously if not feeding as much then fish growth will be slower, but that's the price you pay. You monitor your feeding rate by monitoring the nitrate levels.

As for 200 kg of fish, there is no way you would grow your Jades to 1kg each. 500 grams would be more than ample eating size. I am going to eat some of mine smaller than that also - depends what size you have available at the time to give you continual supply.

My 2500 litre system that I plant to build soon will have only 4 of Murray's grow-beds, meaning approx 1:1 ratio. I am going to try and grow 200 fish in this system. I reckon this will be okay the way I plan to manage it.

Thanks VB, the penny drops


How big are your 30 fish? Are they around 500gm?
Just trying to get a feel for fish-weight:growbeds.

Cheers
jamie

Hell no - biggest would be less than 300gms. Wait until your fish get to that size, you will be tempted to eat them (they look fairly big).

I was probably overexagerating with my comment about my 500 litre bed only just keeping up with the 30 fish. If I feed just once daily there is no issue and my bed is not fully planted at present. One issue I was having was the with evaporation and transpiration reducing the quantity of water in the system the nitrate levels would rise accordingly. This problem will be gone once i move my fish into a bigger tank. Currently I probably only have about 6-7 hundred litres in my system tops. At times it will be half this while waiting for me to do a top up.

Phew
That's a relief.
But this article is very interesting.

He suggests 500kg of fish a year will let him harvest 3,000 head of lettuce a week!

That is a lot of growbed potential.

I's take anything that willow says with a grain of salt. He is rather prone to exageration - might not be in this case, I dunno.

Respectfully VB, a feed to bed ratio with no number to work from is by no means 'all academic'. Feed is relative too. A 3 kilo pacu eating lettuce and fruit will have less 'usable' waste than 2 kilos of high protein carnivores. Or even 2 1/2 kilos omnivores.

And when the temps too high or low, and the fish won't eat their alloted amount?

An ongoing production can keep within a relative fish weight and growbed ratio easily.*

Ratios are given as they work. They are not concrete AP is a natural system with many buffers. Keeping close to the ratios will see you doing well without needing to panic and change things constantly.

As fish grow on you remove the biggest and add some little un's. Well, I do, same with plants, it's very simple now the hard yards have been done, but without guidelines it can be a nightmare of chasing the fine edge around.

If you lack the growbed to match the fish you need to change water as in Aquariums. 1/2 the growbed of the ratios, change the water 1/2 as often as recommended for Aquaria, or change 1/2 as much at the same interval... If you lack the fish add Seasol, or Earth Juice, or both.... these should be used VERY sparingly, coupled with fish waste and good bacteria they seem exponentially stronger in what they do. ie: I never went over 1/40th strength and had great results.

I have years of hassle free system because I did the math and I offer these guidelines so people don't have to spend years chasing their tail around and coming to the forum with dead and dying fish, no plant growth, etc. You'll also find ratios in Joels work, Dr Sadovys, the original S&S design...

Differing types of plants in differing stages of growth. Plus fish, preferably different species and sizes so that some hit eating size around the same time you are 'fully stocked'. Fully stocked is only that you are close to the stocking limit of the beds you have. It's entirely possible to get the numbers up and keep them up while continually taking product out, that's what it's about, for me and many others.

I'm hoping I don't see a whole bunch of folk with 100 fish to eat at once, but it seems to be looming. Guess there's always frozen fish, and veg.

*Fingerling supply is the big drawback in this as they seem to only want to sell you hundreds of fish. If you can breed your own or start splitting smaller buys, you'll be much better off for continuous food production. Saving grace could be natural selection, some get bigger fast, remove and the next come up the ranks.

Your ratio matches mine VB - 1 kilo - 50 litres....

or 30 x 300 gms = 9 kilos - 450 litres (you have 500) Plant it out fully you'll be able to stop worrying about nitrates and start harvesting food and fish.