Bacteria Question

[adelaideaquaponics]

Gday All, Just wanted to throw a question out for comment.

I am looking at running trout in my system in Adelaide and will obviously have fairly low water temps. Most of the info I have come accross suggests the bacteria in the system perform and exist better at higher temperatures (mid 20's).

Any thoughts from the forum on how consistently low water temps might effect the bacteria and my system would be appreciated.

[Jonathan Dyer]

Very little difference almost hardly detectable but, watch your pH is not too low or you will experience a temporary bacteria crash; as I believe I have recently experienced, pH is more vital than water temperatures.

You will get slower growth in bacteria however, this can be offset with more bio-filtration and it doesn’t have to be in the form of a grow bed; trickle filters are just as good if not better, this will support larger numbers of bacteria counterbalancing operating lower water temps. Over winter my water temps were down to 7C and the system was able to cope with its current load; more load = more bio-filtration.

[Outbackozzie]

The temp of the bacteria, as long as it is over 5 degree c is not of concern.

It will just multiply slower, but will still keep up with increasing fish load as they grow.

As JD said, keep the ph up towards the low to mid 7's for best results from plants and bacteria.

[Murray]

Hi AdelaideAquaponics,
The clay pebbles you have in your system will tend to keep the pH down towards the 6 end a bit. I bury egg shells in the grow bed. Get about 200mm of stocking fill with egg shells that have previously been microwaved to kill any possible baddies.

The egg shells are calcium carbonate and will slowly adjust the pH up to the mid range between 6 and 7.
The egg shells will be slowly eaten away by the low pH
Replace the egg shells if and when necessary.
If the pH gets up a bit the egg shells will not be eaten away. The pH will be balanced.

[adelaideaquaponics]

Thanks Guys,

I have been running the system with heat in the mid 20's to help it cycle a bit quicker and was hoping I wouldnt cause the bacteria to crash when I get back to operating temps in the teens when the fish are in.

[Outbackozzie]

Nope, it will be fine, a lot of small systems fluctuate by up to 10 degrees a day, so a gradaul drop back to operating temp wont hurt.