Backyard Aquaponics
A place to discuss aquaponics

Guys,
I just completed my first ibc tank a couple of weeks ago.There are 50 tilapia about 3 weeks old.The fish are doing really well,however my plants are not growing that well.Could it be that at this size the fish are not putting out enough waste to properly fertilize the plants?I tested the water and the nitrares tested at 0ppm.
Thanks,Mcfly

Nooooo! Don't add more fish! What you need to be testing right now is Ammonia. That's what what your fish are producing. Once they create a decent amount of Amm, bacteria will turn it into Nitrates, then different bacteria will turn that into nitrates. Have you tested for Amm? Get a test kit if you don't have one. How much grow bed do you have? If it's just the size of an IBC, I'd say you're way overstocked. I have 45 fish to fertilize ~4 IBC size growbeds. Post test results for Amm, nitrite and nitrate as well as your grow bed sizes and we can help more.

Patience my friend, you wont see good plant growth for another month yet.

As kthignight24 says: how much filtration do you have? Or put another way whit is the volume of your grow bed? 50 fish for a IBC system will be too much and you will run into trouble.

As Charlie says all you need now is patience.

So I was thinking 25 fingerlings per IBC for the brand new systems I am building is that still too many? I ask that becuase I am going to pickup a batch tomorrow. The system is prestarted with bactiria from my inside fish tank.

Than you for your replies.I was not considering adding more fish,just wondreing if the ones I had were not putting out enough waste because of the size.The person I bought them from said 3 fish for every 1 gallon was a good ratio.They are blue tilapia.The test results confirm what you guys were saying,
amm-0-.25ppm
nitrite 0ppm
nitrateoppm.Whatlevels would you consider ideal?
Thanks again
mcfly

Also, what is your ph level? Not that there is much you should do about the ph, but having a high ph may be part of the cause. I know that it has affected some of my plants. Others are fine. I just chalk it up to my system not being ready for said plants... That would be the expression, not actually adding chalk, because that would keep the ph high.

The best ratio to use is # of fish (at their harvest size) to grow bed volume. There a ratio that floats around here, but I don't know it off the top of my head. Anyone?

Are you talking about a 1/3 IBC growbed? If so... based on my setup (which has been successful) you'd be looking at more like 15. Anyone who has a single 1/3 IBC growbed can chime in.

Once your system is cycled, Amm and nitrites should stay at 0 ideally. There's a lot of wiggle room w/ nitrates. If it stays at 0 and your plants aren't doing well you need more fish or some organic fertilizer (maxicrop, seasol, chelated iron). If it gets too high it will affect your fish, but really, I've been cycled for 11 months now and I've only taken readings occasionally for curiosities sake. Fish and plants have done well.

As for now, expect to see the ammonia continue to climb, then fall as nitrates climb, then fall as nitrates climb (unless you have so many plants, they're eaten up immediately). I don't know how much amm/nitrites is too high (do a search on this forum), but just be slow and cautious w/ the feed and you're probably fine. Remember... the more food you feed... the more amm they produce and fish can live just fine w/o food for a week or two. When in doubt, take it slow so your fish stay happy and if your plants aren't either pull some out or add some of the aforementioned fertilizer. Enjoy and post pictures!

The reccomended ratio of fish to growbed volume is 4-5 fish per 100 L of growbed volume based on harvesting 500g plate sized fish