Backyard Aquaponics
A place to discuss aquaponics

i visited a texas parks and wildlife saltwater hatchery last month and your fry tank looks incredibly similar to what they use to hatch out red drum and sea trout.

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Nice work Ben , please keep this thread updated, now subscribed

really interested in your evap tower design, you have any pics?

I don't have photos of that cooler and it's dismantled at the moment. I wasn't really proud of the engineering quality and the look of it. I had a very small budget and not much time when I slapped it together but the outcome was phenomenal.
The concept is:
Two blue barrels top and bottom cut out and bolted together( using the taper to have a tight fit) to create one cylinder.
A 12v car radiator fan sitting ontop (god bless the inventer of cable ties) blowing upwarts.
Underneath the fan is a doubled up shade cloth followed by 300 of those donut shaped kitchen scrubbing pads($30) from the nearest 2$ shop. All tied together in bird netting.
Followed by 6m mister cable bundled up and suspended.
All that sitting ontop of my sump.
At the bottom of the cylinder I drilled 40mm holes as air intake as close to the water surface as possible.
I bought a mister patio cooler set online. $39 and made to hook to water mains with a timer.
A 12v fountain pump(ok with restricted flow) on a new timer and inverter and so on was good enough to see a 2000l system trough a hot sydney summer. There were 3 days I run a chiller (when night time temp was above 28c and days well above 40) water was 23c.
I'll take photos of the one I am building now and post them here.
Thanks for your interest.

Ahhh i get ya, i was bamboozled until i realised the "sitting ontop of my sump" part, i thought you were spraying mist and not catching it again. Sounds very similar to the commercial massive one ive seen and it works well.

I was thinking of having a crack at a cascading tower of flat platform steps sorta like zig zagging back and forth down the tower in a thin layer but i was going to make it from glass or plexi and i can just imagine the mats of algae now.

How much power does the 12v fan draw? did you run it without the fan to see what sort or results? i suppose with the little amount of time its used each year its fine and counter current heat exchange is far more efficient.

I haven't run the thing without fan cause I wired it up with the pump on a timer from9am to 4pm(hours of direct sun)
Starting I had the mister just below the fan and all it did was blowing water out. So reversed it and still had droplets forming on the cloth making their way down to the sump.
I think you need a decent airflow to actually chill and without fan there wouldn't be much.
Degassing btw is taken care of as a nice side effect.
Glad you understood (was kind of hard to describe)

When I heard chiller, I pictured some commercial refrigeration system. I like the simplicity of your design though.

I have a 1kw marine chiller as backup. But try not to use it long term for energy bill reasons.
I used it during hatching to keep temps constant. It also heats so you always stay in the 1degreeC it's set for.
Great machine but expensive to buy ($2300 on special) and to run(1000w).

Here's an update on my little ones:
Had all going good with temp fluctuating 2-3 degrees night and day.
Had three dead for obvious birth defects.
Turned off the uv steriliser and 24 hours later I had the first of three "good" ones die.
Again one side gill plate swollen.
Turned the uv back on and all ok.

Here's your photo with scale colum:)

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The viewing tank

Lost 256 fish in one day!
Opened the lid at 6am and had about 50 dead.
The afternoon before I spend pulling strawberry, capsicum and passion fruit plants out.
So disconnecting the growbeds was my first action. Around 12 it slowed down and from 4pm there where no more dead.
All Api readings are fine, so is do and salinity.
Running on ras only at the moment trying to find a reason for it.

Has anyone ever experienced a sudden rise in mortality after disturbing grow beds?

I took a sample and get a full analysis of the water at that time.

Here's a photo of one. No signs of infections.

Could it be too much nitrate? No more plants to suck up the nitrates?