Backyard Aquaponics
A place to discuss aquaponics

TT needs to keep his opinions to himself after the second beer. Sorry man, killed an ant with a sledgehammer. None of us deliberately try to kill fish and perhaps next time I will engage brain first, keyboard second.

LOL, sometimes I wish there was a breathalizer on my keyboard, and at times my voicebox as well....

did you mean ammonia between .25 and 1ppm?

really need to know the water temp Jimmy
high pH and high temp makes ammonia even in small amounts to be very deadly here is the chart

& is a chart with narrower increments in the 1st edition of the Backyard Aquaponics Magazine :-)

Spot on DRD.... missed the post with the test results.

Agree with DRD completely James, and a combination of high temp and oxygen depletion would probably have been enough on it's own....

Suggest no feeding for at least a day or two and daily tests....

You shouldn't be registering ammonia and/or nitrites at all if the system is cycled ..... how often and how much are you feeding??

Perhaps the high temps took a small toll on the bacteria and reduced there numbers a tad?

I often register small levels of both ammonia and nitrite - but never anything to worry about at all. I assume this is because it has been produced and at that point is being processed.

That would make sense I suppose if as Gotfish says the bacteria had been knocked around with the pump being out and haven't as yet re-established enough yet to fully process everything.

Just clarifying, ammonia - according to the chart on our test kit - was definitely between 0.025 and 0.1 ppm. It was between the two lowest points on our chart.

But, given that the bacteria are apparently killed at temperatures higher than 49 degrees, and in the last heat wave it got to 45 in the shade (growbed is in FULL SUN all afternoon), it is likely the bacteria toook a hit. It looks like another major mitigating action we could take would be a shadecloth sail over the growbed in summer, removable in winter.

Looks like the combination of DO, high temp & borderline NH3/NO2 levels may have accounted for our Silver Perch deaths.

Still getting small Bass turning up dead at a rate of 1-2 per day. They are generally missing their eyes and have varying degrees of mutilation - suspect predation by large Silver Perch (or Goldfish?), or aggressive fellow Bass? Or else, the distribution of their tolerance (to DO, NO2 etc) may be uneven, and given that the system has been operating on a knife-edge lately, that may account for it?

Sounds like a good idea James.... not only stop the plants and bacteria from frying but will keep the tank water temp down a bit as well.... hence keeping DO higher....

Sorry to hear about the Bass.... how many fish do you still have in the system and how many did you start with?

Of the Bass, it's impossible to accurately gauge their numers (there are large rocks in the tank and at any point in time some or all may be hiding). I suspect we may have lost half of the original 100. We have about 8-10 large (~10 cm) goldfish looking healthy, and I believe we're down to one silver perch (over 10cm) - but it looks good.

When we started, the cold uncycled system claimed about 100 perch, then about 10 more, then about 15 catfish, before we managed to keep some goldfish and silver perch alive...

So far we are providing an excellent example of people with no fish-keeping or aquaculture experience, who looked at the pretty pictures of healthy tasty fish and massive leafy greens, built the system according to the book with no idea how to manage it, just blindly thinking it was simple and easy, and have paid a heavy price for being so naiive.

Most of my posts could be put in a "what not to do" file...

The "what not to do" file can be even more useful than the "what to do" file sometimes.... especially for others just starting out

I don't believe anyone, here at least, has conducted a test to show how temps alone affect the bacteria's ability or health. We do have the information reguarding the temps they like best and luckily for the most part (I think), when temps are not optimal the fish will eat less and produce less waste thereby requiring less bacteria to process. Thats the balance?
Maintaining a higher DO would be the best solution for the spikes.
Just thinking out loud.

I thought that bacteria, as living organisms, have a range of temperatures in which they can physically survive (listed in the BYAP Magazine as 0-49 deg C), and within that range there are varying degrees of biological activity, especially reproduction/growth. Optimum is listed as 25-30 deg C.

So in cold temperatures, it's going to be almost impossible to grow a population of bacteria (which seems to be how we killed our first batch of silver perch). If temperatures drop to freezing in the growbed, you could kill your colony. If the temp goes above 49 in the GB (which may have happened in ours, in full sun when the pump stopped working) we could have killed our bacteria too.

It's a fine balance - you need to pump through the GB to cool it down, but this transports the heat back into the fishtank and affects DO levels. We've hopefully solved the issue of DO with the additional air pump.

Perhaps we should also plan to modify the return line: basically bury the pipe in a deep trench and use the ground as a heat sink (currently the return line is 40 or 50mm white pipe, just sitting on the ground). Have to weigh up this work versus installing a shadecloth sail...

sounds like a job for VB's backyard lab