Backyard Aquaponics
A place to discuss aquaponics

400L FT, 200L GB
Canna Aqua clay balls
Flood and drain bell siphon
35L/hour air pump with air stones (shared with another system)
2000L/hour water pump with in-line flow rate adjustment valve
Eheim aquarium water heater set to minimum (21C)
Located in greenhouse in almost full sun

Shade cloth draped over FT and over sides to reduce algae. Now wrapped with 4mm Rhino cell insulation, folded in half.

Was initially home to 52 small/medium sized yabbies with stacked bread crates and cut PVC pipes until silver perch fingerlings arrived.

Looks good

(based on your earlier thread) if i understand it right, then my guess is exhaustion and stress.
Your pumping 2000ltrs per hour through a 400ltr fish tank, and that is a massive water fluctuation up and down with each flood and drain cycle, and is very likely you are killing your fish with stress, in fact i would bet on it.

What else concerns me is 52 yabbies and silver perch and murray cod, all in 400ltrs is bad juju.
Yabbies, even though they are still small, still add to your bio mass, so, there is also the risk of massive over load.

I would suggest filling your tank to almost full, bin the flood and drain (and that heater) and run constant flood, add a bed (if you can) if not, then grab a smaller pump and slow your flow right down to say 1000ltrs per hour max. Keep your aeration up.

I can not imagine the stress of 52 yabbies fighting for space in such a small area. Yabbies are intolerant to fast flowing water, and with the water turn over you have, it is to much for them.

I hope this helps a little.

Regards

thats one bad growth(in a good way)

Hi Porter, although the pump is rated at 2000L/hour, I adjust the flow rate to encourage the siphon to start and cut off as well as possible. The slightest biofouling in the 19mm pipe slows it right down even when the valve is fully open. I will eventually add larger pipes or completely overhaul the system to a different design.
I timed the flood and drain a while back, and found it takes between 7-9 minutes between cycles. A variance of about 55L.
Yabbies were randomly dying right from the beginning, which I attributed to high density. I later purchased a second hand system, with 4 half IBCs, pipes, pump, a few fingerlings, and a barrel of fish feed, and much more for $100. (No pictures up yet)
Limited for space in my square greenhouse, I sat two halves on top of the half bases. One half IBC used up all the Hyrdrocorn I had already purchased, and I am experimenting with a raft system in the other half. I plumbed the 2 bottom half IBC sumps together so that one overflows into the one with the pump.

There was much less fighting after I seperated the yabbies into a male/female in the half IBCs. Some of the females were berried, so I am temporarily using the raft tank as a hatching tank, and then remove the mother into the female tank once the babies leave her.
So after some fatalities along the way I only had about 10 adult yabbies in each tank.
A few days after adding the fish, they seemed very comfortable swimming right near the yabbies without any dramas. Although now I am wondering if both the yabbies and fish are stressing each other...

At one point I did remove the siphon and ran as constant flood. I added a down pipe so that the water falls silently below the surface. I don't recall if that was before the mass deaths occured or not.

The surviving fish in the seperate system are still doing fine, and just recently most of the remaining adult yabbies have died, plus one Murray Cod. Since I seeded the new system heavily water pumped from the original system, I am worried the water itself is contaminated...

What???

No matter how much water flow there is, it will not change the water level much with only the one growbed on there... And why do people insist that water fluctuations are bad for fish? It's a made up idea with no basis in fact, fish deal with water fluctuations all the time...

True that!

I'm really liking your system by the way Asi_9, it looks awesome! it's builds like this one that keep me inspired to continue doing AP, and to keep dreaming about the large system I want to eventually have.

Keep up the good work!

Thanks thsdragoon! I'm in the process of rebuilding my system at the moment.
I want to squeeze 4 growbeds into the 3x3m greenhouse. Currently have 2 growbeds running.
Made a few mistakes, but still learning.



Sent from my iPhone using Tapatalk