Backyard Aquaponics
A place to discuss aquaponics

Yah that's what I was thinking, but doesn't hurt to ask.

The plan was always to pull them out if the water temperatures got over 20-22°C if I hadn't already picked them off for dinner before then. I hadn't read anything about what feeding does at higher temps, it'll be handy to know once the temperatures climb, I really don't want them to suffer or stress out.

There's no way I'm even going to attempt to keep them over summer, I don't like my fish boiled, lol.

I'd think above 22 degrees, you may be beat just to stop feeding. It is likely the trout will be absolutely fine for a period of no feeding (studies show that not a whole lot of condition is lost when fish are not fed), and just wait out the hot weather, assuming no super extends hot spells.

Above a certain temperature the FCR goes to hell as well, so feeding them is a bit of a waste!

That strategy will work very well for me because even in summer my temps are rarely above 20 but for most people not so much because the wait for the hot period to end may be rather a long while.

Yeah, I think it will be quite the challenge for me to keep these trout going, but, if I can work out a robust and failsafe way of doing so, it will be great

The first part of this problem is determining your final objective: is it to keep the fish alive, or, do you want the fish to flourish and rapidly grow like they might in optimum growing conditions? The first is a very small challenge compared to the latter!

As some might know, I had "reasonable" success over-wintering barra in Perth in an outside system with no additional heating; heat was provided by the sun during the day and retained as best I could using insulation, "topping up" the heat as required from ground water which had a pretty constant temperature of 22C. It was an "interesting" problem and learning curve; it took considerable additional daily effort. I've already started thinking of the reverse of the process, to over-summer trout in Perth in an outside system with no (powered) cooling. I think the principles are pretty much the same (in reverse) i.e. keep as much heat off the system as possible (reflective insulation), avoid pumping water through large heat-sinks (GBs) during the hottest part of the day, exploit every opportunity to cool the system and as a "worst" case replace the hot water with cooler (ground) water (there will be some nutrients lost to drain, but if the fish and the plants survive...) My system is only small, so I didn't have a lot of thermal mass to play with which exacerbates the problem, if you've got the capacity then exploit that too. I think in over-summering trout, the DO will become a very sensitive trigger for failure, so I reckon if you can increase air pumping (there is heated added here, but it's not that significant) and reduce the stock density to as low as practicable (and cost-efficient) the chance of success may be better, but is it worth it?

I learned a lot from my over-wintering barra experience, so I hope you have a similar (positive) experience, although I did promise myself I wasn't going to do it again and just keep the right species in the right season... only time (and SWMBO) will tell!

I'm not sure but are you thinking of running the bore water through the system? I'd have thought that would strip away the nutrients and end up being more like a flow through aquaculture system. Which could well be what you're planning now that I think about it
Have you thought of sitting the IBC in a pond that the irrigation water passes through to maintain temps?

Well, to flourish is the idea, and to get that we really need to keep the temp under or around 20 degrees.
Given groundwater here is 18 degrees, and that we pump 10kL (or more) a day for watering all the lawns, it should really be no issue in keeping the constant temperature.

I will have some pretty serious aeration through, with the help of this pretty serious air pump: http://www.hailea.com/e-hailea/product1/V-60.htm





We're not going to use this tank in an aquaponics sense, we'll just concentrate on the trout at this stage

10kL of water on the lawn!

I still have trout from last year. Tank temps did get to 26°c once and caused swim bladder problems to a couple.
There were 6 fish in 5kl of water. I did not feed them when the system temps were over 22° which was often. Cool nights, low humidity, water volume, shading, insulation, paranoia and minimal power failures kept them going.
Lack of nutrients, stress and time were issues. Sure I have a few big fish I can fillet and brag about but I would not do it again, nor would I recommend it. PITA.
Stock to the ambient conditions and save yourself the worry.

Lot of lawn! :s
Also is tall fescue which is very thirsty, especially with the slightly (900ppm) water.

It's my parents place, and the lawn is getting the watered either way, so I mose well take advantage!

****Slightly salty water that is.

Also been thinking of turn ing the pump of for say the hot 6 hrs of the day but wont that just inject quite hot water back into the system when it cuts back in?

It would, but i'd say you'd still be better off doing that than pumping through the day.
You could even hold off pumping until the water in the GBs cooled off a bit.