Backyard Aquaponics
A place to discuss aquaponics

Hi all, need some advice...quick! Currently have 31 Barra ready for harvest,( all about 30cm+) in size. Have taken 3 out and they were fantastic!! Anyway, did a water test tonight and got some very strange results. Everything was fantastically balanced about a week ago but then the water went tea coloured due to silt I think. Did plant some new things,(silver beet and Broccoli), about 2 weeks ago. Have managed to clean the water up again and the older and newer plants look fantastic and are growing well. My main concern is that the ammonia levels have jumped to around 8.0 but the Nitrite levels are at 0.0 ?? What has caused this and what can I do to get it right before the fish suffer?? Any help or advice would be greatly appreciated. Cheers!

Do a second ammonia test and see if the value is genuinely 8.0 Do you have another test kit? Or, test some distilled water to see if your ammonia test solution has not "gone off".

If the ammonia is 8.0, then what is the water temp and pH and how close to ammonia toxicity are you?

If too close for comfort, I'd harvest the fish before the succumb and die; if they die a quick death at your hands they are going to be edible, if they die slowly in the FT they will release all sorts of chemicals and nasties into their muscles and flesh in their death throes and may not be safe to eat, wasting the entire harvest.

If you still have some latitude with regard to TAN toxicity, do the usual water change. "Dilution is the pollution solution." Prepare your system for the inevitable nitrite spike after the ammonia spike; pray the high ammonia concentration hasn't "sterilised" the system and killed the good bacteria.

As for what causes sudden elevated ammonia levels, other than the fish; look for uneaten foods or other contaminants, dead fish, mice, frogs somewhere in the system. Have the fish changed their eating/swimming/behavioural habits recently? Could someone had tampered with something? Did someone (with good intentions) accidentally add a few litres of Charlie Carp? Has the pump been off for an extended period? Have you had any run-off from rainfall? Where did the silt which you think discoloured water come from?

I'd have to asume that the system is being heated... if the Barra are still alive...

Regardless.. the ammonia is far too high... 50% water change immediately...

And don't feed....

Personally... I'd just harvest them...

fishbound, what happened next??

Ok, so this is the latest, bunsen. I took your advice and re-tested the water...same results. Tested some distilled water...proved my test equipment is ok and accurate. Since then I have taken out 13 Barra. Man they look good!! I probably should mention that this is my first harvest and have only been doing aquaponics since September last year(2011). So I am super stoked and happy with the results so far. My tank is approx. 800 litres and I only have one grow bed but have managed to raise 34 barra, (minus 13), and a stack of great veg. I have just ordered a second grow bed which should make my life easier in terms of keeping things balanced! Anyway, being so new to all this means my knowledge of what works best and how to achieve the best is very limited. That's why I'm so worried about my water tests and fish!! The other bad thing is that it does appear that the water is "sterile" as I still have a 0.0 reading for Nitrite levels but ammonia and Nitrate are still very high!! That's about it for now. Cheers!

With no fish in the system, the ammonia will fall as the bacterial colonies sort themselves; the nitrates will fall as the plants use up whatever is there.

Have you though ahead about the next step, what to do next?

Not exactly. I mean, the next step is to try and balance the water while trying to keep the remaining fish alive and healthy. I bought some bacteria to try and boost my system today. I just can't harvest them all...don't have the freezer space. I plan to install the new grow bed asap. in the next few days or in the next week, complete harvesting the barra before trying rainbow trout over the winter period. What do you think?? I also have another question. What do you think about using polystyrene foam sheets to float on the water surface to help keep warmth in, or will it leach stuff into the water, then plants and fish?? Love to hear your thoughts as it sounds like you know what your doing. Also, what would the critical level for ammonia toxicity be for barra? Cheers!

Ammonia toxicity is more pH & temperature related... than species specific...

What does that mean... I'm new to this! Can you give me some idea of what kind of levels would be toxic to my barra or what I should be aiming at. The fish look great, all about 30cm+ in size...they were perhaps 5cm long when I started. This is my first year in! Don't want to lose them. Cheers!

This might help explain ammonia toxicity

Sent from my HTC Wildfire S A510b using Tapatalk

Thanks for that. Very helpful! Cheers!

At an Amm reading of 8.0 your pH and/or water temp must be fairly low... and seeing as they are Barra I would say it's your pH and not your temp... do you know what they are?

Out of curiosity, what area are you in?... what are your current daily water and air temps?

...and as far as the trout you are considering, no matter where you are I think you have nearly missed the boat for this year, unless you by yearlings.

Like Rupe said, rip the Barra out, share them around the reli's or neighbours if you don't have the freezer space... and if you are in an area suitable for trout and your temps are low enough then bang the trout in a.s.a.p.

This might be a stupid question, but I don't get the chart. I understand the temp and ph, but what is a good number and what is a bad number?

It varies... as an example:

At a water temp of 20º and a pH of 7.4... Amm will become toxic at a level of 2.1.

However, at a water temp of still 20º, but a slightly lower pH of 7.2, Amm will become toxic at the higher level of 3.2

The lower the pH and temp, the less toxic Ammonia becomes.

Clear as mud?

I have an aqauponic system and the water in the fish tank and the veggie beds are the same 7-7.5 normal..My understanding is to have healthy. Veggies the water should be between 5.5and 6.5.How do I bring down the Ph in veggie beds when system has consitent flow of water from one tank to another..Need help veggies are turning yellow