Backyard Aquaponics
A place to discuss aquaponics

This is not good at all, temp droped to 5degrees.

Hi Jaco, did the fish survive?

Yes Martin, so far all the fish are still alive, The water temp is currently 8degrees, don't think it went lower that that. I kept the pump off most of yesterday and during the night.

Well I'm glad the fish are still going. What minimum temps are you expecting for winter? You might have to resort to heating which might become expensive quickly.

The lowest that I got last winter was 3 degrees, I'm going to make a solar heater soon.

Ok cool. One of the problems you might have is the small size of the system. When you have a big system the size of the body of water buffers your temperature. Then if you can raise it in the day it takes longer for it to drop during the night.

Can the fish you have survive 3 degreees?

Regards, Martin.

They won't survive 3 degrees (Tilapia) but the water temp should not drop that far, when the outside temp was 5 degrees and I got alot of hail in the GB the FT water temp only droped to 8 degrees. With a bit of external heating I should be able to keep it above 10 degrees. The insulation that I have arount the FT helps alot to keep the temp up during the night.

It sounds like (touch wood) you're getting it under control. I don't want to jinx it or anything.

Keep the updates coming Jaco.

Regards, Martin.

I hope so. The guy that I bought the tilapia from keeps his fish outside during the winter without any real problems, unfortunately he does not monitor his water temps so I have noting to compare mine to.

On another note, I'm going to do an ammonia test tonight but the instructions says that the water temp should be between 20 and 30 degrees C, is it realy neccesary to bring the water up to that temp?

No, you don't have to heat it to their ideal temperature. You only have to keep it above their minimum survival temperature to keep them alive but then be aware that their feeding and growth rates will drop dramatically. Give a bit of a buffer between your tank temp and their lowest temp you don't want to lose them through an accident like someone unknowingly unplugging the heater or something like that.

Martin, do I need to heat the water for ammonia test to be accurate? Thanks for all your help so far.

Jaco I actually don't know. I am not much of an expert on ammonia testing. I can tell you though that I have never seen anyone state that they heated their tank in order to do an ammonia test.

You want to throw that question at someone like Charlie or RupertofOz (there are a few other guys who could answer too but they spring to mind first).

I wouldn't want to make a guess and give you the wrong information.

I heated a glass of the water slowly to 25 degrees and then took the test, looks like my ammonia levels are in the 0.25mg/l range. Will test it later in the week again.

Hi Jaco,

I would suggest you download and read the IBC of Aquaponics here: http://ibcofaquaponics.com/
It is 187 pages but it is very pitcure/photo intensive so it is light reading. At the end there are is a description of the Nitrogen Cycle and a number of useful tables including the "Ammonia Toxicity Scale" (page 187) which shows what levels of ammonia are toxic to your fish.

The document also covers the plumbing and most other aspects of building a system. It is a treasure trove of good ideas for building your own system.

Regards, Martin.

Thanks Martin, I was looking for that link (clearly not very had), had read it a while back but it's time to read it again. I have a pretty good understanding of the nitrogen cycle, I just don't have alot of patience.

For now I'm not going to do a partial water change, as it is raining so much, have to drain 10% every other day to stop FT overflowing.