Backyard Aquaponics
A place to discuss aquaponics

I would apreciate some feedback on my water readings so far. Now that I have good numbers of fish in I would like to know what I can expect from hear going forward.
My readings are as follows with the history so far in the chart below
PH - 6.6
Ammo - 1.0
Nitrite - 1.0
Nitrate - 10

I'd keep a sharp eye on ammonia and nitrite spikes while things adjust. Things will probably stabilize in a week or so.

Here's' a basis for my thoughts: if the bacteria can double in a couple days and you started with capacity for 1kg of fish (just roughing some numbers):
after 2 days you can support 2kg
after 4 days you can support 8kg
after 6 days you can support 16kg
after 8 days you can support 32kg

I think you should keep an eye on the pH. It is dropping rather quickly.
Be careful that it does not drop too low as it could knock out the establishing bacteria...

Hi Ivan
I am going to get some shell grit tomorrow to try and buffer it back up and stabilise the PH. I was a bit surprised at the sudden move myself.
I am also expecting the Ammo to climb now that I have started the trouts feed rate.

I tell you what but, I love watching the little fellas smash the food. I is so hard to not just keep feeding them

I hope you are not feeding them food by a percentage of their weight already. You need to bring both ammonia and nitrite
close to zero before doing so.

Depending on temperature and pH, ammonia becomes toxic at different levels.

And salt to 1ppt to mitigate the nitrite level...

Nope.... well while it's true that the bacteria can theoretically double in a few days...

Like all living organisms... they need food and oxygen to do so....

Suggesting that you can tie stocking density to bacterial growth... alone... is fraught with danger... and totally disregards the surface area/volume of media required to support the bacterial colony...

And the oxygen requirement...

Agreed. That's why I used double in two days rather than the optimum 1 day. Also why I said to keep testing for nitrite and ammonia spikes: the numbers used are suspect, but are a general guide: perhaps doubling every four days rather than two might turn out to be more accurate. Either way, if he already has healthy bacteria for some fish his cycling time will be far less than starting from scratch.

Thanks for the info guys.

I have salted to 1ppt on Saturday morning more for the stress relief side rather than Nitrite spike but it is in there now regardless. I am going to put shell grit in tonight when I get home as I do not want the PH to continue to fall.

On the subject of the Ammo I was of the understanding I still had a fair bit of room to move here. I have looked at a chart that was posted by Rupe that sugests that with a water temp of around 12 deg / PH = 6.6 then the toxidity level for Ammo is around 25. Dont get me wrong as I will not let the ammonia level get any where near this (2 was going to be my upper limit) but I thought I could mitigate the ammo levels using water partial changes if and when required. My water source is rain water that has a natural PH of 7.2 and no traces of Ammo/ Rites or Rates.

Please feel free to jump on me if I am heading off on the wrong path.

Well yes, the chart shows the ammonia, pH and temperature relationship. But you did say you will be getting shellgrit to raise the pH, so you have got to account for that as well.

From memory, 1 unit of ammonia will produce more than 1 unit of nitrite (I think 5)... so yes, ammonia could be safe at 2, but your nitrite might be higher and hence more toxic. Salting to 1ppt helps, but I am not sure how high nitrite can be before the salt loses its benefits.

Water changes only slows down the cycling process, hence the best would be to cut down the feed. IMO, try to keep your ammonia and nitrite readings 1 and below, if it goes up above 1, skip a feed.

It might be a good idea to track water temps in the same chart.

Very nice Design, I love the thought you have put into it all. Keep up the good work!!!!!

OK Aper's this is todays readings

PH - 6.6
Ammo - 1
Nitrate - 10
Nitrites - 5

Is this the nitrite spike I had to have ???
I have previously salted the water to 1 ppt on Saturday. Should I increase the salt to mitigate the Nitrite ??
Should I lay off on the feed for the next couple of days as well ?

In my experience, the colour for nitrite above 1 is hard to determine whether it is 1 or 5. But the point is that
you don't want your nitrite to reach even 1. There is no harm is salting the tank slightly more, but I am not sure
that it will mitigate the nitrite any more. I think you can bring the salt level to 3ppt without affecting plants from
growing, except strawberries apparently.

I certainly think you should stop feeding for at least a day or two. What is your feed rate at the moment?

I agree with Ivan, it is hard to read the nitrite sample, maybe a picture, your ammonia is ok considering pH, my pH has been 6 for weeks and can't get it up, but don't want to stuff around with it now, reading a few other threads a few west ozzies are experiencing drops in pH, may paranormal activities or "The Day After Tomorrow" about to happen but nitrate at 10 is fine, I would think from that your Nitrites are less than 5