Backyard Aquaponics
A place to discuss aquaponics

Hi All,
I was wondering if anyone had experience keeping trout alive over summer in Ballarat or Melbourne - and what tips you have on doing it?

My plan was an aquaponics system in a greenhouse with silver perch in it (because it's generally very cold in Ballarat - about 4 degrees cooler than Melbourne, and usually feels like 9 months of winter weather).

Then to have a separate external trout pond 1m deep x 1.2m wide x 2m long above ground, with a deeper middle section 2m deep x 1.2m wide x 1.2 m long under ground... so total depth is 2m below ground, 1m above ground. The pond would have aeration and would be surrounded by wood above ground, with an openable lid. (I was going to set up a bottom drain with an overflow pipe that feeds into the greenhouse - but the overflow would only be used at certain times - see below.)

Do you think this would enable trout to survive summer, maybe with the odd day of ice packs in the water? Any other design improvements? Would it help to have the above ground portion smaller so there is less exposure of the wood to the sun, or to put insulation or reflective material in?

Also because the water from the greenhouse system will be a bit warmer - do you think it would be sufficient to just set a timer to do partial water exchanges/changes (maybe 15-25% of volume) with the greenhouse AP system each night - with no additional pond filtration (or this pump could run for a few hours each night when the greenhouse system cools)?
In this situation would the pond need any additional circulation, or will the aeration suffice?
Alternatively, I could just set up a small filter box connected to the pond with some lava rock (for a larger pond biological filter + water circulation), and cycle the pond water all day; and then do the partial water change with the greenhouse each night.

Is one decent sized air stone enough? Is it more about the amount of air flow than the number of air stones?
Thoughts or experiences anyone? Thanks.

Bump

Anyone?

Maybe check Gungullas system threads. Hard work keeping trout in warmer conditions.

viewtopic.php?f=18&t=16345

viewtopic.php?f=18&t=24153

Ice has negligible effect unless you can add a fair amount in relation to the total water volume.

You'll need a lot more ice than you think, if that is your plan. The calculations I've done have their own thread here:
http://backyardaquaponics.com/forum/vie ... modynamics

and

viewtopic.php?f=7&t=22552&p=468494&hilit=334kJ%2Fkg#p468494

If you get your fish in january they should be up to eating size by summer saying that you can keep them over summer with an aquarium chiller and a remote filter all in a cool spot , I kept fish one summer like that just because i could , but do you want $35 fish
But you cant use grow beds as filters as they are a good heat sink
I even tried burying 40 meter of pipes 2 meter down dident work

I liked carrying trout through 2 seasons to get the extra size for fillets and easier to pin bone.
I didn’t like the stress on hot days while I was at work worrying about returning to a tank of dead fish.
My advice would be to build the set up but leave the trout out the first season or 2 and have the number of fish in the greenhouse split between the 2 tanks and monitor the outside tank parameters during the heat spells.
Or plan on single season trout but accidentally leave a couple over summer to test the waters.

If you use solar power, a 2735g fish like this can cost under $15

That’s a beauty Guna, well done. I’m am curious how the $15 cost is calculated though.

Marginal cost of power from a PV system is zero, so if you can buy feed at a good price, or grow at least some of your own (you'll need about 3kg of it for the fish above, my pellets were $4/kg), then the only other small expense is keeping the water chemistry optimal.

Thanks mate, not bad 3kg feed for a 2.7kg fish!

I kept detailed records and worked out from my first batch of 80 trout that I got 94% of the pellet feed weight back in fish, with only occasional additions of snails, slugs, slaters etc.