Backyard Aquaponics
A place to discuss aquaponics

Hello everyone,

I'm recognizing, that's quite a sad title for my first post.

I started my first experiment a few weeks ago. To keep it simple I build an IBC tank with some mechanical filters and some lime stone as biological filter. I didn't implement any grow bed yet, so at the moment it's more an aquaculture project than an aquaponic project. I'm planning to add the plant part when I have a suitable place that offers sun and is frost prove.

The system works as follows:
The overflowing water of the IBC tank (approx 900l) is collected from the bottom and is let to a swirl seperator. From there it goes into a buffer tank, where the pump is located. The pump power is approx. 3000l/h.
The pump sends the water through an addiitonal filter with sponge and lime stone filters. (This one is intended to provide a surface for the nitrification bateria.)
From there the water flows back through a pipe with multiple small holes into the IBC tank.

I started with 20 small trout (approx. 15 cm). At the beginning everything looked fine, the fish was behaving healthy.

I took daily water samples to see when the first ammonia would turn up. (I expected to have no nitrification bacteria at that state. My plan was to exchange the water if ammonia level would rise too much.). However ammonia level was almost zero all the time. (Ph was approx.

After the first days I noticed that I couldn't see my trout eating. (I'm not sure if they ate at the beginning). As there wasn't any high amount of ammonia in the water I assumed that oxygen level might be too week. However, I never saw the trout at the water inlet, which I would expect if oxygen level was too low.
After approx. 1.5 weeks the first few fish died. As I had no idea what to do, I added an additional pump with approx. 3800l/h , that only circuleted the water in the IBC tank to enchrich it with oxygen.

I also exchanged half of the water, but that didn't stop my fish from dying. After some more of the fish died, I decided to cancel my experiment. I put the rest of my trout into our lake in hope they will survive there.

Now I'm wondering what I might have done wrong. I talked with some local fish guys, but they couldn't give me any satisfactory hint.

Therfore I would like to put here a list of possible reasons to discuss with you.

1. Ammonia test not working correctly? (Used new solution at an aquaristic shop)

2. I used well water which we also use as water supply for ourself. The water is very calcareous. Is it possible that it disturbs the function of the fishs gill?

3. Trout feed too big to eat? I used "offical" trout feed with a 4.5mm grain size. However, I would have expected the fish to at least try to eat it even if it was to big.

4. Too much oxygen? I don't know if this is possible. I got this hint from someone, but I don't know if this can be true

5. Some kind of infection? After approximately one week some of the trout got some kind of white fungus at their mouth. I was told that this is likely due to injuries that can occur when the fish is beeing caught. It shouldn't be deadly, but occurs when the fish has other health problems.
Not all of my trout had this fungus.

It seems that I might have been a bit naive when i started this project. Next time I want to do better. Therfore I appreciate all constructive comments. If you need further information on my systems I will gladly try to provide all that is necessary.

Thank you for reading.

Howdy Rockwurst welcome to the forum.
More than checking the ammonia I believe what you need to do is cycle the system properly.
https://www.fishlore.com/NitrogenCycle.htm
The limestone as a filter material also concerns me. Get an API Master test kit and check the pH level. Limestone is probably throwing the pH to the Base side of the scale. The pH measures the range of the water from acidic to the opposite end which is base. Limestone is heavy in base. Test the pH of your tap water as well. Find out if the tap water is acidic or base.
http://www.backyardaquaponics.com/information/the-nitrogen-cycle/

I hope this helps

To add to that last comment - if your pH is high because of the limestone then it takes less total ammonia for toxicity to be an issue as you can see from the chart located here - http://ibcofaquaponics.com/information/tables-and-charts/
My best guess is that you had a spike in ammonia or nitrite either during transportation or once they were in system and damage that occurred at that time is slowly taking it's toll.

Salt the water to 1 part per thousand (1 gm / 1000 ml) to help the fish with stress and help them build a slime coat which will help with the fungus.

I think you may want to let the well water aerate for awhile before use, especially if you are adding a large volume.

I didn't see your pH listed but I'm guessing it's at least 8.2 based on your description hopefully you can get that posted along with any other parameters you have. A photo of the system might help also - sometimes fish can get caught in pipes or injured in other ways.

As Scotty stated definitely aerate your well water. If you are not aerating your well water before putting it in to the fish tanks you could have too much nitrogen. Any gaseous nitrogen over 100% in solution can be deadly and it is called supersaturation. The "disease" that it caused is called gas bubble disease which is basically the bends In fish. As long as you aerate your water before your fish you should be good. To have too much oxygen in your water to cause problems you would have to be running pure oxygen and injecting it in the water with both the water and oxygen under pressure.


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Trout can handle a 9 pH but as mentioned before the higher the pH the deadlier ammonia is. Calcareous water is fine. Trout use the calcium as flux to help oxygen pass through their gills. What size were your fish? Grams?


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I might have to look into my fish disease book to see what type of fungus they had. How were their fins? Can you give more physical descriptions of your fish?


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Thank you for all your replies.

I'm sorry. I wrote down the pH value, but it was turned into a smiley.
I tested the pH value every few days and it was always 7,5-8, according to my test.

@boss: I read about the nitrogen cycle and I believe I undestood it.
As I was pretty sure, that I don't have any of the needed bacteria already. I tested my water for NH4/NH3 on a daily basis. It is a test where you have to compare the color of the water after you mix it with the indicator liquid. It goes in the steps 0mg/l, 0.5mg/l, 1 mg/l, ...
I found it to always be between 0-0,5 mg/l. (I couldn't resolve it any better by eye).
I also tested for NO2, but there was definitely no indication for nitrite.


I would have expected to see a rise in the NH4/NH3 level and then I would have waited for the nitirde to appear. But as already mentioned I never saw a clear indication for it.

Is it reasonable that I didn't see anything? I had a bit of fish poo and some residues of my fish feed. Is it likely that the ammonia/ammonium level is almost zero if these are in the system and there are no nitirification bacteria.

@scotty435: Do you think it is possible that an ammonia peak appeard and I didn't see it? Maybe i have a bit of nitrification bacteria that reduced the ammonia before measurement. But shouldn't I then see any Nitrite?

So just adding a bit of salt to the water helps the trout? I never heard about that. But it would be easy to do that. Thank you for the idea. Are there any other household chemicals that I can use to prevent my fish from getting deseases? I was suggested to use Wofasteril classic (https://www.kesla.de/produkte/wofasteril-classic/) by a professional trout farmer, but it's quite expensive for a small system and not so easy to get for a private person.

@ crackenfish: I cyceld the water for aproximately one week, before adding the fish. Do you think that's enough to remove the excessive nitrogen?

So calcareous water is off the suspects list.

I didn't see anything special on the fins. Some were a bit white at the outer skin close to the gill. But that seems to be normal, as I found images of trout with similar appearance. I will look if I find some usable images on my phone. I took some pictures, but never checked if they were ok.

One week is more than enough for gaseous nitrogen(N2) but not for the nitrogen cycle.


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Very sorry for your losses. Hope the rest pull through!

-K98

Salt helps the fish a lot. What is that product that you linked? Unfortunately I can't read in German and there wasn't a translate into English button.


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Yes, I think you missed it either because it happened in transit before the fish ever went into the system or there was a problem related to testing or the timing of the test. I also suspect based on your description of the system and it's calcium carbonate content that the pH is higher than 7.5 to 7.8, although stranger things have happened.





If the pH is higher, then under certain conditions you wouldn't even have to reach the lowest reading of the kit for the ammonia to be toxic.

I may be wrong about what's going on but it's fairly common to loose fish early on because of ammonia or nitrite spikes. There are lots of possible causes when it comes to fish deaths - it could even just be stress or a combination of factors.
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Yes, salting does help (helps them build a slime coat and reduces stress, higher amounts can be used to treat diseases). You'll find lots of references to this if you do a search here or on the web. Salt is pretty much all I've ever used in the AP system. Wolfasteril classic is probably strongly antibacterial since it's used as a disinfectant and I would expect it to kill off your biofilter if used in AP.

Thank you for the feedback.

@crackenfish: WofaSterial is peracetic acid.
You might be right that it will effect the biofliter. At least it drops the pH of the system quite drastically.
The guy who recommended it to me told me to be very carful about it. I don't know for sure the effect on the biofilter. The guy didn't do cycling but had a steady water exchange.
However, I know Koi-people also use this stuff and they also rely on the biofilter.

@scotty435: I can hardly imagine, that such an ammonia peak can happen so fast and without any trace. But maybe I'm a bit naive.
Is there a better (inexpensive) way to test the pH value than using a test liquid? There is always a chance, that I read the color scale wrong.

Maybe I can try to use water from our lake next time. I'm sure it will have a lower pH.

I found a short video of my trout on my phone shortly before they were released into the lake (https://we.tl/cXQP0WVDsm). Maybe some of you guys can give me further hints from their appearance. At the end you can also see the water inlet. The small inlet, was the first one I installed. This one comes from the filter system. The bigger one I installed later to get more circulation into the tank.

Please also note the movement of the mouth. I'm not sure of the rapid movement is usual.
I also attached an image which shows four of my dead fish. Maybe this gives you also an indication on what went wrong.

Do you have an idea of the size of fish in grams?


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Have you had any hot weather , trout are finished if the water warms too much.

Hello,

@crackenfish: I think their length was approx. 15 cm. I think their weight might have been around 150 gramms. But I didn't measure it.

@Terra: heat was definitely not aproblem. I'm located in Germany. We are at the beginning of winter at the moment. That means water temperature was between 8-10° C.