Backyard Aquaponics
A place to discuss aquaponics

aftere seeing Boris01's fish and the quantity of food he was feeding per day with the same grow bed volume, I think i was feding at the upper limit of what the system could handle, a few small knocks pushed the nitrogen as ammonia and nitrite over the top and they died. I have let it sit for a week, and am introducing more fish. So far they are healthy and eating well. The water was quite turbid and chunky when they died, but now its crystal clear again so im confident it was over eeding and water quality

May have been food on the bottom of the tank? ... I think the culprit has been found.

no way is it food on the bottom. THe air pump blows soo much air across the floor that nothing collects there, its all suspended. ALso they eat practically all of it before ti gets to the bottom
I think it was overfeeding over a long period that acumulated ammonia in the system tll it got to a critical level.

How often do you test DP, because of the cold weather we have had (even in Perth) your Ammonia would have to be reasonably high to kill them all so quickly

I dont test...

three more died today. Two were left from the last batch, and one from Boris01.

I think this rules out a been and gone contamination. THe three that lived from the last batch were living in the sump where they excaped to. They were not fed as much as the others.

I keep my food in a plastic bin next to the grow beds. I am at the end of my bag of food. Could it be the food has gone off and the fish are getting food poisoning? Ie fish salmonella?

The few remaining black bream and silver perch arenot dying, but htey eat much less

Have we ruled out heavy metals leeching into the system yet? Could be pH was > 7 and so you weren't seeing an effect, but as soon as it goes below 7 it dissolves some of the metal and your fish get heavy metal poisoning?

Does that food container get warm? I keep all of my food inside, with only a couple of days worth outside.

Any chance of mice or rats getting into the food and contaminating it?

The food container is black , in full sun , and gets blown over regularly ...

I suggested heavy metal poisoning today and got yelled at .
convinced its bad food now - that food smells slightly wrong

Fish food (especially high protein stuff) does not keep forever, especially in warm conditions. I keep my fish food in an air tight bin, in the shade, with dehumidifier packs. I don't have enough space in the house to keep all feed in the air conditioning but I'm going through the feed pretty fast, been having to go get a bag a month lately. Come winter here when I won't be going through the feed so fast, it will be cooler out in the garage so that is ok too.

You're kidding me.. aren't you...

"Get's blown over regularly"... what by blowflies...

yeah its outside in the weather, but the lid seals. No vermin get in, but it could get warm

yesterday i did a 90% water change, and got fresh food. I also moved the remaining silver perch and black bream to the tank furthest from the grow beds. So far no deaths.

I will now store the food bin in the shed, and have got a smaller tub and measuring scoop so i can store a small amount in the cupboard under the cleaning sink. THe scoop will give me a better idea of how much food they get each day.

Sounds a good plan to me...

Yup

Well the good plan didnt work!!!

4 died yesterday, 8 today the remainders will not last till tommorow by the look of them.

These are new trout, eating new food, living in new water.

people are suggesting getting the water tested, but for what??? THe local university can test for a range of things, but the tests are expensive and each test only looks at one thing. Eg lead, or mercury, or organophosphate. It would cost hundreds to have it tested for everything.

Can water be overoxygenated? how much is too much oxygen?

Not really... it can be super-saturated and problematical if using pure oxygen injection with really small bubbles...

In a standard AP system utilising air... no...no such thing as too much oxygenation...