Backyard Aquaponics
A place to discuss aquaponics

Nitrite takes longer to cycle than ammonia.
So it is entirely possible for nitrite to spike higher than ammonia.
The nitrosomas (ammonia converters) will have built up quickly and are converting everything to nitrite, but the nitrobacter (nitrite converters) havent caught up yet, so there is a backlog of nitrite

Fish are all still alive this morning.

Levels are as follows:
ammonia- 0.25ppm
nitrites- off the chart, a real purple rather than lavender
nitrates- 5ppm
water temperature- 12degC
pH- 6.8


I had seen the chart Rupert has included before, so I wasn't so concerned about ammonia at the low temps we are still getting. I am still surprised by the nitrite levels.

Maybe this info is important? The fish were never really fingerlings (unless you have freakishly long fingers). They would have been back in March, but we received them in September, so they were between 7 and 15cm. And the 7 cm one died yesterday morning...

I guess they would produce a lot more waste than smaller fish, but conversely, would they be better able to handle toxicity in the water? The early death of the little fish seems to suggest that...

Again, thank you or your help.

At least with tilapia, the smaller fish are less sensitive to nitrite for whatever reason. I also thought that the smaller fish produced more waste per gram because they are growing, but I could be completely off base with that!

Chloride (from salt) has been show to increase nitrite tolerances, so there's that...

I picked up Nite-Out II (http://www.microbelift.com/products/hom ... te-out-ii/) and used that during cycling. I was up and running in less than 2 weeks, but it was also really hot out (40-45 C during the day). If you can find it, it certainly couldn't hurt throwing a bottle (or two) in.

So, I apologize for throwing in a stupid question here ,but how do you get the salt ratio (ppt) is there a salt testing kit ?
I've also seen here ,salt should be added when introducing fish to a system (1 g / liter )
Best of luck with your system Blythe.

Salinity refractometer.

Thanks Charlie

Because I'm a geek and I'm cheap, I figured there have to be other ways to measure salinity without buying a unitasker (as Alton Brown would call it).

I have an ohm meter. Salt increases the conductivity of water, so I should be able to measure the salinity with my ohm meter! My little experiment did show that there is a clear measurable difference between water straight from the tap vs water with an arbitrary amount of salt in it (a pinch or two in a shot glass). The problem was the pure water had a range between 5k and 12k ohms depending on how much of the probe was in contact with the water and possibly the distance between the probes, and the salt water had a range of 2-3k ohms with the same variables. Too much inconsistency there.

I also have a digital scale! Adding salt to water increases its density. I should be able to weigh a known volume of water and know what its weight should be if it were pure and subtract the difference. Unfortunately, my scale isn't accurate to the gram, so I'd have to weigh a very large volume of water.

I think I'll go look for a refractometer.

OOH! Maybe I can build one!

You can get good refractometers for about $40 on ebay.

Id like to see someone make one though

Good news on the fish front. Except for the little one which died, all fish in System 2 are fine!! And the levels are:

ammonia- 0.25ppm
nitrites- 0.25ppm, hurrah!!!!!!
nitrates- look like they have gone down again, between 0 and 5ppm. Not sure what the story is there.

Yesterday morning, the nitrate levels were 2.0ppm, so they really come down fast!!

Out of interest, how long can fish go without food if the water is around 12degC? My other AP system stayed at .25ppm ammonia for a long time, and I didn't wait util it reached zero before feeding again. Do I have to wait until it is definitely 0ppm?

Vegetation looks good in the system, too, except that it is being nibbled by something. Still need to ratproof around the doors.

So, all looking good, YAY! I didn't end up moving any fish, just salting and adding more O2. Thank you all so much!

Welll I admit it, I was wrong.

I would never have thought they would all survive that. Well done

Hi Blythe,

I will not claim to be a fish expert, but given the levels have dropped fairly quickly, you are obviously getting a good colony of bacteria happening. Your levels are out of danger now, I would be tempted to give them a small feed. Just an appetizer really.

I remember feeding my Barra when cycling with similar levels, and that worked. Mind you it was a small feed.


Cheers
Wazza