Backyard Aquaponics
A place to discuss aquaponics

Hi,
I have started an 800L IBC aquaponics system with 15 x Silver Perch fingerlings (10-12mm).
Water temp is about 20C and ph 6.4
I am cycling with fish. I am feeding them very small amounts.
They have been in for 1 week now and I am testing the water regularly.
So far I have detected no ammonia.
With this size tank and amount of fish, when should I expect to see ammonia start to build up?
Thanks

Can take a while.

Keep the feed to a minimum as when it does appear it will take a while for the conversion to start.

Be patient, it can take up to 6-8 weeks for the system to be established.

This time of year in Melbourne it will probably be quicker, but just take it slow.

Thanks for the reply. Do you think if I haven't seen the ammonia spike after over a week with (very small) fish, then it probably won't spike but just rise gradually? I've been feeding them small amounts regularly and they seem active and healthy so far.

Hiya tlin05, welcome to the forum.
15 x 15mm fish aren’t going to create an ammonia spike in a new system such as yours, the system will grow with the fish. Adding 15 x 150mm fish would likely give you a spike. Leaving uneaten food in the tank may also give you a spike.
In my opinion how you are doing it is good however the plants may not get enough nutrients with such a small fish load.
How are you testing the water parameters?

Thanks Skeggley,
I'm using the API Freshwater Test Kit for PH, Ammonia, Nitrites, Nitrates.
Is it worth adding small amounts of nutrients for the plants or is that just asking for trouble?

Hardest part of new system is waiting.

Don't be adding or messing with too much till the system has cycled.

The plants will be fine in the short term. Give it 3 or 4 weeks and see how the readings are.

Keep waiting, be patient.

Thanks Brian. Sounds like good advice. Will do.

I agree with Brian, patience is a virtue.
But, how will you know when it’s cycled if you never see ammonia?
If you’re adding trace ammonia in the form of pellets and the fish are adding trace ammonia due to their size then trace nitrite and nitrate may be seen although the plants may be taking all the nitrates leaving none....
If you are seeing no readings on any water tests after 1 month cycling, I’d be tempted to add an organic ammonia source in the form of Charlie carp or powerfeed in small doses to a) add nutrients for the plants b) prove cycling. Starting with 1/2 cap added via watering can to grow beds weekly until proof of cycling in the form of nitrates or nitrites.

Almost 2 weeks in. Will give it another 2 weeks and see where we're at.
Thanks

My aquaponics system is 6 weeks old now.
As can be seen below there is still no detectable ammonia, nitrites or nitrates.
Fish seem OK (hard to see but they are still flitting around at the bottom of tank) and I haven't found any dead ones - or at least none have floated to the top.

Most plants also seem OK although were shredded a little by a recent hail storm.


One thing I forgot to mention earlier was that at time of adding fish I also added 100ml ESTABLISH startup bacteria. No idea if this has had any impact.
I'm not going to add anything to speed up the nitrogen cycle, and let it establish at its own pace.
My fear of ammonia spikes and stress on the fish seem to be unwarranted.

You're right!

The fish sound like they're happy/hungry and your plants look healthy.

So you can test less often. The fish will get bigger and eat more as time goes by and the system will adapt.

Some people never see ammonia or nitrites... And those with light stocking and/or plenty of plants might not even see nitrates.

Before long, you'll stop worrying about ammonia and will be trying to work out how to keep your ph up [WINKING FACE]

But it seems like you've been sensible about your stocking rate (how much wet media do you have). And you've started with small fingerlings. So you should be fine.

Many plant deficiencies can be managed with foliar spraying if you don't want to put anything in the water.

Enjoy watching those SP grow!


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