Backyard Aquaponics
A place to discuss aquaponics

I set up an aquaponics system at my school in a greenhouse. After running wonderfully for 3 months my 25 tilapia died in the span of 1 week. I believe do to chlorine build up. Anyways it is too late in the year to grow fish up to harvest level before the end of the year but my plants are huge and producing. What can should I do to keep my plants getting the nutrients they need? I could buy more fish or just gold fish but don't feel right just killing them all in 3 months when I shut it down for summer break. Any suggestions would be greatly appreciated.

Thanks
Kyle

Hi Kyle, welcome to the forum and sorry to hear about the fish.

I doubt that chlorine was the problem. Usually just letting the water stand for a day is enough for the chlorine to dissipate - Chloramine is another story though. Considering they all died around the same time you probably had some sort of physical problem like temperature, ammonia or nitrite problems but there are other possibilities.

You can keep the system going by sprinkling some blood and bone meal around on the grow beds. If I remember right, I think the amount of blood and bone is about 50gms per 100 gallons of grow bed. You'll need to repeat this process at regular intervals.

+1 to blood & bone, you may have to add small amounts of liquid seaweed or a multi-element as well.
depends on what you have growing.

main one is to keep the light out of the system to avoid algae.
Keep it circulating and good splash to keep oxygen in the water.

Thanks guys... draining my tank today I found 1 lone survivor left in my tank. I found someone that would take goldfish for their outdoor ponds for the summer so I might buy some of them and keep the fish fertilizer going.

Did your fish die from a particular disease? If not, I wouldn't worry about it. Just like in our environment, disease organisms are usually present in low numbers in the aquarium. Give the aquarium a major water change, wait a week or two and go ahead and start adding fish as normal.

If the fish died from ick, raise the water temperature to 90 F, keep it there for 3 weeks and then loaf the temperature back to normal and do a large water change.

In extreme conditions, you can break the tank down completely, bleach everything, rinse everything well, fill the aquarium up with water and heavily dechlorinate everything. After a couple of water changes and dechlorinating until you smell no trace of chlorine, you can treat the aquarium like new. All the gravel should be removed before adding bleach. You can spread it outside and let it dry under direct sun, turning it several times. The drying, heat and uv light should sterilize everything. If you are going to this extreme you might as well toss all your filter media and start fresh. If you do this, it is the same as starting with a brand new aquarium and you must cycle it again.