Backyard Aquaponics
A place to discuss aquaponics

Hi all,

My 50 Jade Perch are dead. If you have any thoughts on what may have caused it please reply as I'm stumped.

I have a recently established IBC system built per the instruction video on BYAP. Flow and drain on an hourly timer between 7am and 8pm with a break overnight. Oxygen supplemented with a 2 output pump with battery backup. System was cycling without fish for 3 weeks. When fish were added levels were PH 8, amonia 0.25, nitrite 0, nitrate 5. Fish have been in for 2 weeks, have been eating well (pellets and lettuce leaves) and have grown visibly in that time. Some plants have been in grow bed for 2 weeks, some for 1 week.

I tested the water yesterday and levels were PH 8, amonia 0.25, nitrite 0, nitrate 20. Last night I fed pellets and a lettuce leaf and all the fish fed eagerly (as usual) except two that sulked at the back of the tank near the surface. This morning when I got up 42 of the fish were dead laying on the bottom. The other 8 were swimming about slowly at various depths from about 5cm below the surface to near the bottom. I pulled the dead fish out and tested the water, PH 8, amonia 0.25, nitrite 0, nitrate 20. Water temp was 23 deg C. The remaining 8 fish died within a few hours.

I phoned the fish farmer who supplied the fish and asked for advice. He said that if my amonia level has been constant (at 0.25) over the six water tests I have done in 2.5 weeks then my test kit must be stuffed and I probably actually had a lethally high amonia level. So I took a water sample down to the local aquarium supply shop and got them to test it, PH 7.2, amonia 0.5, nitrite 0, nitrate 5.

So I'm completely stumped an would love to hear from anyone who has any ideas what might have caused such a sudden die off.

Here are links to vids I took this morning of the fish (mostly dead) in the tank, and of them in a plastic container after I took them out.
http://youtu.be/I64ORRVWF-A
http://youtu.be/xO8_j_wJn-g

Thanks so much for any thoughts.

If your ammonia levels were actually closer to 0.5 ... and have been for several weeks...

Then they are fatal levels at pH 8.... but not at pH 7.2....

Although pre-longed exposure to ammonia would probably be detremental to small fingerlings...

I'm also trying to figue out your system... a breif glimpse on the video seem to show an hose input into a silver cyclinder... what is that???

A second media gaurd suggests a standard overfloe standpipe... correct???

I'm also puzzled as to why you were turning off the timer/pump from 20:00 - 07:00 ... especially as you're located in QLD....

Not sure when you measured the water temp at 23.... but it's possibly been a lot hotter than that, even overnight....

And, regardless of the air pump.. (what size, and was it working)... it may well have been a combination of ammonia and lack of oxygen....

50 Jades in a single IBC system is pushing it aswell, especially in one that has not developed.

But I am very sorry to hear of your fishies, dont let this get you down and hopefully we can help you figure it out.

Ok thank you guys. I didn't understand that interplay between ph and ammonia.
Thought I was just on upper edge of acceptable ph range but didn't realize ammonia toxicity varies with ph.
I will get ph down before replacing fish. Will also add fewer fish.
Also will monitor temp better and up oxygenation.
Re the period of timer/pump off during night, two reasons: 1. The IBC is outside our bedroom window and my wife is a shift worker. 2. I read on an aquaponics site that it is good to give the roots a break during the night. There's a lot of conflicting advice out there. You think keep it running overnight?
Re the filter on input to grow bed. Nothing special. It was to clear up residual cloudiness due to clay pellet dust. My other hobby is amateur mycology (mushroom growing) where we often filter airflow by pushing it through holofil (pillow filling) so I transferred the habit to my IBC setup.
Yes it's a standard overflow standpipe.
Cheers guys.

It always helps to get a better idea of your system if we can see a photo Please?
Fish require oxygen particularly at night time and it sounds as though turning off the pump during the night didn't do you any favours. We have systems here that have the pipe extended in to the fish tank, rather than allowing the water to splash on the fish tank surface. This makes it much quieter, without turning off the pump. Better luck next time Tallman. Oh and by the way, don't believe everything that you read about aquaponics, there is a lot of overselling being done. Have patience, read lots and enjoy your system, there are lots are people here to help, so don't be afraid to ask.
Have you downloaded the IBC of Aquaponics? There is a lot of info in there and the stocking info is designed to grow fish safely to plate size. (50 fish sounds like a lot to me )

Definitely keep running overnight... especially during summer...

The only time I turn off the timer.. is overnight during winter... to keep tank temps up as much as possible....

And only with supplementary aeration through the night...

Can you link to the site that suggested that the "roots get tired".....

I'd love to see what other gems the site, or poster suggested.... (not having a shot at you Tallman)...

But I'd love to see what sort of logic the poster applied to arrive at the suggestion....

Perhaps the roots get "tired" from swimming all day long... maybe we should provide individual "floaties" for all them ittle bitty poor rooots....

P.S... my plants having been doing that well lately.... probably because it's been raining most nights...

Can someone ask "Hughey" to stop the rain overnight... it's tiring my plants out....

P.P.S ... can someone ask "Hugehy" to just stop the bloody rain fullstop... I'm bloody tired of it...

Thanks again.
Good point Faye, I'll take and post a couple of photos. Have just got home from airport and it's dark now in Brissy.
Re the aquaponics site and the notion of giving roots a rest, to be fair, the author actually says:

"Many aquaponics enthusiasts also like to program their timer so that the growbed is not flooded at all at night. Flooding the growbed at night is certainly not harmfull however some gardeners believe that not flooding at night accommodates the plants night time needs more."

So I don't want to paint him/her in a negative light. I took that comment and ran with it.
Anyway the site is here: http://www.diyaquaponics.info/how-aquaponics-works.html

So I'll have a look at extending the standpipe down to water level to quieten it and keep it running all night. I now have a nice little list of things to fix. Thanks.

Shutting down at night is not a problem if you have relatively light fish loads. It isn't necessary but some people do it (I've done this in the past), mostly it's to save money on electricity or lower the noise. There may be some reasons relating to holding the temperature of the fish tank up or down as well. You will want to run air to the fish tank just won't be running the water pump.

Do yourself a favour Tallman... ignore that site... and most of the (mis)information it contains...

The author demonstrates their complete lack of knowledge.. and obvious hydroponics bent... by maintaining that a bottom up tray fill... ala "ebb & flow" hydroponics... is the same as a timer based "flood & drain" aquaponics system...

And goes on in other places to repeat absurd stocking density recommendations...

Funny part is... from the website registration... I know the area where they're located... and most AP systems around there.... and neither I, or anyone else close... has ever heard of the man... or his systems...

My roots are submerged in running water 24/7 and I have never observed bags under their eyes.

Thanks all for the advice.

I have changed the stand pipe for one that extends all the way to water level, and this has made the system quieter. Drilled a couple of Venturi holes near the bottom of the pipe so now getting much better aeration than with the old pipe.
Changed the timer to run 24/7 with the growbed full for a bit longer during the heat of the day.
Posted a vid giving a brief intro to my system - it's quite jerky as I did it with my iPhone. http://www.youtube.com/watch?v=cQhFk9akY-A
Measured levels Saturday 4 Feb: PH 8.2, ammonia 0, nitrite 0, nitrate 30.
Measured PH of tap water (which is what I filled with in mid Jan: PH 7.6.
Added some additional lettuce and pak choy seedlings.

The system has no fish in it at this time.

Should I just wait for the PH to drop naturally and sustain the plants with Seasol (if the nitrates drop off) before adding replacement fish?

Thanks again.

At 8.2ph, something is buffering the system. Without an ammonia source, no nitrification would take place hence the ph would probably stay at that level.

Sent from my GT-I9000 using Tapatalk

My guess is lack of DO when you turned the system off overnight. A small air pump wont do much in an ibc. I killed 5 out of 10 jades doing the same thing a couple of months ago. All water readings fine but realisd that turning off the system overnight allows the beds to drain and the sump to become oxygen poor. Then the pump comes on pumping low DO water into the fish tank
just my 2c

Wow, yeah that's a new one for me... Seems there are a lot of plant and fish whisperers out there recently..