Backyard Aquaponics
A place to discuss aquaponics

Hi guys,
Trout went off feed yesterday evening. 48 trouts in 1000L tank, 2x 500L BYAP growbeds. System is over a year old now. Heaps of aeration. Tested water yesterday, traces of ammonia and nitrite. pH is below 6 (I think). Added some garden lime. Switched pump to manual overnight.

This morning, ammonia and nitrite zero. pH still below 6. Still not interested in feeding. No floaters or sinkers that I can see.

Did notice a bit of fish crap in the tank. I think the pump strainer is too small to allow the bigger fish crap to be moved to the growbeds. After running overnight, I found some fish crap stucked at the pump strainer. On turning off the pump, backwash cleared the crap away. Took the pump out for a bit of a flush...

Did a bit of a water change. Did not check the salt level, but will possibly do so later...

Anyways, not sure there is much else I can do. Just wait and see. Stop feeding for a day or two.

Have read Ivan that trout will go off feed when the weather changes, I was in Perth yesterday and was some storms off the coast, if water tests ok then don't change anything, don't feed them for a day and see if they come back to feed, mine go off in the morning but eat in the arvo

I experienced the same thing, trout didn't want food before the storm. Temps dropped, I personally think it also has to do with barometric pressure, but that is just a gut feeling. Will monitor and observe, interesting that you are seeing the same thing Ivan.

Hmm... good to hear that I am not the only one then. But the funny thing is that I have single lone trouts in two other systems (one AP and the other just a powerhead filter). They seem to be still eating... but pH in those systems would be higher...

This evening still not really eating... some initial splashes but after that, no splash... some uneaten food removed... the good thing is the tank is clearing up though... The bigger poo is still not getting moved to the growbeds as suspected the strainer is too small for the poo to get through...

So will definitely not feed them tomorrow. So yes, will observe and hope that they will return back to normal...

Did you see my thread? Interesting I just had a ph crash myself on the weekend. Trout went off feed, ph below 6.

Take a look at my thread to see what remedies I did.

Cheers.
James

Yeah... read your thread... I have also watered in some Ecorose... hopefully that would help bring up the pH....

my pH is on 6 now and has been so low that it wouldn't change the colour of the test solution, has never effected feeding, I thought it killed my new batch of fish but was a couple of dead yabbies that did that, I'm sure Joel said when I was having problems that he also had low pH without a drama, TM has said he knows lots of people with lower pH than he has, all cause no problems, I could almost confirm that low pH is not why the fish are off the feed, I have a feeling that the dead yabbies caused my pH to crash though but I can't be sure, I would be making sure the tank was clean of dead things or uneaten food, but remember *frack* ing with things is more harmful than good, a day or 2 off the feed is not the end of the world as long as fish still look ok

Ours are back to normal feeding today... Quite happy..

I have a bit of a theory about the whole pH bacteria thing, not based on any particular science (I don't have a microscope or a lab) but rather observation over time and general experience of many different systems. There must be different strains of bacteria that do the conversions of ammonia/nitrites at both different temperatures and different pH.

Sudden changes seem to be the thing that messes most with a system, and this can be temperature, salt, dissolved oxygen or pH, these changes can cause a crash of bacteria populations.

But in a system that slowly sinks to levels of 6 or below and continues to operate and function well with ammonia being converted? This goes against most of the conventional information that I've read which suggests that all nitrification will stop at a pH of 6 or below.. Well I don't know whats going on down at that microscopic level, but I've seen plenty of systems down that low and performing really well...

Thanks guys. Well I am not sure about the trouts today. Left for work early and will not be back home until late this evening, so I guess I will find out tomorrow.

I think the nitrification is still happening in my system since the traces of ammonia and nitrite were gone the following morning. If the bacteria has crashed, then we would have likely seen an increase in ammonia.

Will test the water tomorrow and try feeding. Hopefully I have good news too..

Agreed Joel... I think the spikes recorded due to any imbalance reflect the fact that nitrification is inhibited by ammonia... especially Nitrospira.... the principal convertor of nitrite to nitrate (see my article Issue 5)....

And that allows Nitrobacter to temporarily pre-dominate... and a reflected temporary imbalance...

Nearly all the mature "amber tea" coloured AP systems... are in a state of perfect balance... and usually a pH of around 6.0...

Yeah I didn't want to reference your article Rupe, I'm afraid some of it went a little over my head.......

And mine too in parts...

Yup, all good... This morning the trouts were feeding with their normal splashes. They probably decided that they needed to detox for 1-2 days...

Nice to hear.

Gee sorry didnt get down your way the other week.

Shaker, no worries...