Backyard Aquaponics
A place to discuss aquaponics

Hi! I have been operating my aquaponics system for the past five years, but this summer I have had a problem with my fish dying that I have not been able to solve. My system has three 64 square ft grow beds and a 300 gallon fish tank. I removed one of the beds in January of this year so that I could rebuild that bed, and ran the system with just the two other beds.  I pumped out the water into a separate Rubbermade cattle trough and an old bathtub while I was rebuilding.  I finally finished the rebuild and pumped the water back into the new bed, and connected it back to the system in June.  I realize this was a huge mistake because that water had been sitting in the trough and bathtub stagnant and growing bad bacteria for 6 months.  My tilapia were already sickly when I was running the system with just the two beds, perhaps due to low water quality as some of my air pumps were out and I hardly had any plants in the system during the spring while I was busy with schoolwork.  After I added the third bed back in and fixed all the air pumps, I put in 5 lbs. of new tilapia.  They all died within a couple weeks except for one.  That's when I realized the water was bad due to sitting for 6 months.  I treated the entire system (1500 gallons of water) with 2.5 quarts of bleach.  Then after nine days, I put in young plants and 5 more lbs. of tilapia, but the tilapia again all died within a few weeks.  While this second batch was sick, the guy at the aquaponics store said to add innoculant bacteria, add 1.5 cups of sea salt (SEA - 90) once a week for 2 weeks then less regularly, and to mince fresh garlic and feed it to the fish before their regular feed.  I did all that.  They didn't seem to eat much garlic, but it seemed like they died a little slower, maybe due to the salt or good bacteria? Four to six weeks after treating with bleach, I emptied out the water from the entire system (although there was a little bit of water left at the bottom of each grow bed and the fish tank) and refilled it with city water that I filtered (which is what I initially started my garden with five years ago and regularly use to top off). I tested this new water with two small batches of goldfish; the first batch all died, but only 1 out of 6 died of the second batch. So I added 2 lbs. of goldfish (approx. 60) on October 5. As of now, over half of them have died. Any insights y'all have would be much appreciated! If you have any questions that would help you to give advice, please let me know.

Any metal in the system in contact with the water? The bath tub is made of? Piping? Any frames for plant supports or shading?

Maybe time to do some tests.
With the water being left for so long there might be something like leaves & bugs dead rotting & giving off Ammonia,or it needs to be cycled again.
Maybe there's huge PH swings & you mentioned city water,maybe the filter you used didn't stop something that is causing the fish death.
Or where you're getting the fish from might be the problem.

I would test the water first PH,Amm,Nitrite & Nitrate & like Brian said check no metal is touching the water.

1) The bleach killed all the bacteria, beneficial or otherwise, so the system must cycle again. Also the bleach may be soaked into the media and take time to dissipate. Perhaps you should check for chlorine.

2) Once added, salt never goes away unless you perform a water exchange, so advice to add salt repeatedly is bad advice. Add salt once and check it regularly. 1 to 2 ppt is a good range to help your fish. Use pure salt with no additives. I use a mix of potassium chloride, sodium chloride and epsom salt. I get the chloride salts from Home Depot. They have Solar salt and potassium chloride for water softeners, and it does not have anti-caking, anti-rust, iodine o=r any other additives. I hear that pool salt and aquarium salt re good sources too. One kg salt to 1000 l of water is 1 ppt.

3) After 5 years your grow beds are probably full of fish waste gunk. You likely have anaerobic areas, especially if you had issues with pumps, air pumps, etc. You may need to clean the media. This stirs up a lot of gunk so should be isolated from the main system during cleaning. Any anaerobic areas will create hydrogen sulfide which stinks and is toxic to fish.

Please send some photos of your system so we can see what the grow bed construction is, the fish tank, etc. Maybe the lining you used for the GB was not cleaned or is not fish safe?

At this time, with so many problems, it sounds like time for a complete reset - clean everything, start with fresh water, treat for chlorine / etc. with Prime or similar water conditioner, fully cycle using clear ammonia and API test kit for monitoring, etc.

As you can see shortcuts usually are only shortcuts to dead fish. With fall setting in and temperatures dropping, it may take some time for the system to cycle, especially after the bleach treatment.

What are your test results for pH, ammonia, nitrite, nitrate???

Lets see a couple photos and some test results, then maybe we can be more help. I hope you get things turned around.

John99 makes some good points. I have reset a system before. I bleached it and let it sit and run. Then i drained snd flushed a few times while stirring the media.

When I start my systems, it uses a lot of water almost 500 gallons. I fill it and crush up 10 vitamin c tablets. Save that expensive carbon filter for top ups, emergency system flushes and water changes (yes i do 10% water change quarterly because i am paranoid about build ups).

First you need to cycle the tank.

You didnt mention how you acclimated the fish. If i just float a bag for an hour and release the fish i will loose 50% or more of them even if they are healthy. Then i get a decond die off latter. I switched to drip acclimating and havent lost a fish. My supplier gives me fish in a 5 gallon bag. I put the bag in a bucket. Start the drip at a few drops a second and add an airstone. Wait for the bucket to fill. Once full, drain half and wait for it to fill. Repeat a 2 to three times and expect it to take all day.

Between sick fish and stress and not cycled you are going to loose a lot of fish.

On another note, you might have stupid high ammonia resetting like that from all organics in your media. I didnt even need to add amonia to my system it was there next day. My amonia was so high it was off the scales and took two and half months before it read zero. It was also during a realy cold Florida winter. When i finnaly started making nitrates, my PH crashed constantly for the last 3 weeks. Thank God i had no fish in it. The poor guys wouldnt have made it. I had to fill panty hose with crushed limestone to the size of a foot ball (American Football since we are different on this side of the pond) and then dose ever 3 days with potash.

Aslong as you didnt use heavy metals or noxious things to build a new grow bed, i dont think you poisoned the water. I remember once a guy used a corrugated steal tank and all his fish kept dying come to find out corrugated steel is zinc plated. Zinc and copper will kill your fish fast thats we dont use the Fertilome Iron chelate, it has copper in it and its a low PH iron supliment anyways. Pressure treated wood is treated with copper. I always make sure the things i use are protected so they dont leach into the wood. My grow beds are made plywood. Next time i rebuild i am fiberglassing the growbeds so i can use them outside.

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Welcome to the forum farmhouseaquaponics, sorry to hear about your fish.

Yes some strange advice from your AP store. Garlic? I’ve been on this forum for a while now and have never heard that advice….
And bleach? Hmmm
Fish parasites will not survive long without a host. Generally fish parasite diseases are visible. Salt = chloride = slime coat = fish friend. Pool salt, cheap. 1kg per 1000 litres, or liters =1ppt.

Yes, metals is possible cause, any brass, bronze, copper or tin in the system? Water source?
How were the fish transported? What colour were their gills?

More information required to get to the bottom of this mystery.

I have heard of garlic before. I dont remember the article but i beleive it was for digestive health. Side note i use garlic in my catfish bait they seam to like it.

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