Backyard Aquaponics
A place to discuss aquaponics

Thanks Gordon,

Sizing calculator wont go so low as my current input, but roughly I need less than 100L/hr and just one GB is way too much.
Rough figures - At 60g per feed per 1m2 GB area, I could support 360g of feed per day. A bit more than the 40-60g /day they are getting.
They look fine and healthy but not eating a lot.

Solution - I need 10Kg more fish asap. And something suitable for temps 18-28'

PS in answer to previous question. Tap water Ph around 7.4 - 7.6.

Jeff

Yes, with small fish you are generally out of range, but small fish, at least trout, eat a higher proportion of body mass of food. I did my calcs for the size I wanted to grow my fish to, as ultimately that is what the system needs to cope with.
Re-run it for your projected fully grown size fish and see how it looks.

Current stocking of 30 Barra. Say to 700g (if they ever start eating) = 21Kg. At 1% = 210g/day.
Still way under 360g.
With no losses, this gives a final stocking density of 17.5Kg/m3 which is at the higher end of suggested OK of 20.
Plus I have the 120 hole NFT system I want to use as well.


I'm thinking my only option is to buy 10Kg of large Koi. Gives the load I need and is fairly stable over time. But they are damn pricey in larger sizes.

No fingerlings of any natives available at present, and I would have to buy 1000 of the little buggers - which then cause a problem next year as they grow...

EDIT - just read about gassing water before reading Ph - will do and read tomorrow. Assuming my 7.4 may be at least 8 - hence the high Ph I am seeing :-)

It's not correct to say that there isn't any fingerlings available at the moment... well depending what you define "fingerlings" as....

And why does it "cause a problem next year as they grow"...

1. My assumption based on limited knowledge but searching and reading trying to find something suitable. I believe Cod come on in December...
Definition is very loose simply meaning "bulk babies that I can get hold of"

2. Because lets say 400 x 25g babies = 10kg (minimum) fish mass that I need right now. In ? months at 250g that will be 100Kg and 200Kg at 500g each.
My problem will quickly switch to become too much fish - which is much worse than not enough fish
I see this progression as obvious but happy to be shown otherwise

Silly example but that's what I need if I start with very small.
Ideally I could get 100 x 100g-150g juveniles (better word ?) that wouldn't overrun the system and be just about ready to take over when all the Barra are removed in Apr 2014.

If I could just decide on the best species (SP or murray cod or other) and then find them at a reasonable price, and transportable to Singleton... I would be very happy

Jeff

Forgot you had Barra...

If your intention is to try and run Barra during summer... then your choice is simply to run trout in winter...

And harvest both when the growth periods dictate... regardless of size..

If you want to run longer term species... then you either need to just stick to one species... or have multiple fish tanks/systems..

Your maximum stocking density is determined by your filtration capacity... at maximum feeding rates...

If you stock larger numbers based on the size of fingerlings.. then you will have problems... probably sooner than you think...

That's the rationale... and mistake promoted by some...

In reality... if you stock the numbers that your system is capable of supporting at max feed rate/harvest size...

And if you're feeding at the recommended daily feed rates/protein percentages.. related to stages of growth....

Your nutrient figures wont change that much.... and your system and plant growth will run just fine....

I'm thinking (can be dangerous...) that one tank with an ongoing population - allowed to grow continuously and harvested on demand, would work well with the 2nd tank that is used over summer for Barra.

Summer I will have more plant growth to use up the extra nutrients of the extra fish, and then winter the system "slows down" when the barra are removed.
Good or bad plan?

Hadn't considered Trout as thought would be too warm. And this year I only have (safely) June onward to start them (due to 1 month absence May). Would only work if I start with decent size - and then the issue is finding a supply and the extra cost of larger fish

And it still brings me back to a see-saw fish density as a mass harvest is replaced with a small load of babies - vege's would have to be culled and then slowly increased in sync.

But it's a thought - thanks
Note 2 tanks.

Ah Ok... just looked back...

Two tanks, 8 grow beds...

I'd go two systems... 1 tank, 4 grow beds each...

And trout will do fine during winter up your way... and are available May/June around 100mm...

Oh bugger...

I found the filter that came with the Koi - full of yucky filtered $#!t. I thought "there is a great bunch of bacterium and NH4 for help the system along".

Well I was right - plenty of NH4 and No2

Hopefully everyone will survive this little spike while it converts...

But on bright side, Ph is sitting around 7.4 without me touching it.

Salt to 2-3ppt and your fish should be ok...

I'm starting to sound like Rupe

"Hey I have a problem with my fish"
"SALT" More Salt!

31 Oct. Bit the bullet and traveled to Sydney for some Koi. Now have 12 ranging 30 -50cm.
No idea of weight but I assume +/- 1Kg so 12 Kg in addition to 4.2Kg barra.
That should help things along
They love the veiwing window and spend all day there - unlike the barra that hide in the dark.

So these will be the base load keeping things going between batches of "other experiments".

Water they were living in (and traveled home in) was Ph 8.8 - 9. Diluted 200L of it into the system (3000L) day 1 and 300L day 2 with no noticeable affects. Overall system Ph climbed a little as expected, but everyone is happy.
A warm day today, barra water 21C they were hungry
Jeff

1/11/13.
Busy week. Managed to kill 5 of my koi by overreacting to a ph of 9.4. Bad calculation obviously overdosed and ph fell to 6. Had 2 floaters in an hour, and despite bring it back to 7.5 another 3 the next morning... 30 - 50cm koi about a $500 lesson.

Levels came back ok although hardness is now 100+. Is this an area to worry about?

7/11/13.
So I have been busy. Got myself 20 new baby Koi - too expensive to buy the adults
Tidied up some of the plumbing, put some control valves in, and made a floating pre-school for the babies.
Just a supercheap storage box, lots of little slots, supported by a pool "noodle". Save having a separate tank. So far so good.