Backyard Aquaponics
A place to discuss aquaponics

I like the bit about you would remember the cool Coolgardie safe are you saying I am old
I just remember them and sides was hessian but if I was doing it I would go for 1 or 2 layers of shade cloth
I wouldn't have it wicking just a constant trickle[/quote]


Milne, maybe your family were a bit better off than mine and you guys had an "Ice Chest" and that's why you only can just remember the Coolgardie.

We didn't upgrade from the Coolgardie to an an Ice Chest until I was 4 or 5 years old so I can just remember it.




I'm getting the message about using shade cloth and not Hessian, what I like about the Hessian is that it wicks and I wouldn't need to spray water all day. I already use shade cloth to cover the whole system plus a shade sail that hangs permanently above the system but it's those few days we get when the temperature gets over 42c degrees.

I've never tried shade cloth to see if it wicks, I don't think it would, maybe use both together??? and not need to run any water.

What I'm looking for is something that will wick up, evaporate and not need to have running water but I'm definitely hearing you all on the shade cloth.

Just a few comments- I don't think shade cloth will wick very well, as the fibres are completely water repellant and not at all absorbent.
Hessian will wick, but not very far when it is hot- it will only be wet for a short distance from the water source in hot dry, and especially when windy, weather. You may need to spray it periodically- or use a misting nozzle. I have one for keeping the chooks cold in hot weather, it uses about 15 litres of water per hour.

There would probably be more cooling potential in the daytime, rather than night, as the rate of evaporation, and therefore cooling, is higher at low relative humidity, which is generally during the daytime. Cooling during the day would tend to reduce the diurnal water temperature range.

Be careful with cooling at night and not during the day- you may increase the diurnal temperature range of the water, which isn't generally good for the fish.

Active cooling of the GBs may be more effective- there isn't a lot of surface area for heat exchange in a shaded FT, but lots in the GBs, and that's how much of the heat gets into the water.

A Coolgardie safe worked like this there was a trough around the top about 2 in deep that held water and the heshen only had to wick 2 in at the most then it ran down the sides
So saying that I recon shade cloth is the go \
yes you will need a light spray on it at all times
I even tried burying the pipe that dident workI have tried most things and posted results in my thread but its getting a bit long now and most cant be bothered reading 130 odd pagers of rant

I would not have thought just letting the material wick would do much at any rate? It might cool the air a little around the tank but not the water much. Having water running down will cool the water before it re-enters the system, hence cooling the system.

I went to buy some smaller trout yesterday and the nearest shop to me was on the last batch of trout this year. They were not in a condition to buy, I was told the water had already gotten to hot for them ??

It is a 2 hour each way trip to the the shops in southern perth so will have to wait and see if i can find some next week when heading down that way. Has anyone seen some healthy trout around perth this week ?

Pete

Just having water run down the material without a breeze going across it won't do much either. I set up a fan on my evaporative cooling system on the stoopid hot days. Yes it does use a lot of water using the evaporative method.
As for getting trout this time of year here in Perth, generally people are pulling their trout October/November as the temperatures warms, the fish begin to stress, stop eating and growing, so I'm surprised anyone is selling rt flings now.

Pete,I may be able to help you out around Christmas time but not sure.A local farmer usually gets about a thousand very small ones and puts them in his dam and I get mine from him but I don't know what will happen this year as he had a storm and they all escaped the cage and now they have a lot of 600 gam plus fish in the dam that would make short work of any little ones that may be there.

This summer im planning on running a separate pump that will be plumbed into a old bar fridge that has a heap coiled copper tube inside returning directly to ft not sure if its been tried before as my ft only 500lts it's gota help a bit what does everyone think

How many watts is the fridge compressor?
If it is say 150W and you get a COP of about 1, then it will, optimistically, cool 500litres of water by about 1 degree in about 4 hours of continuous running, if the air temperature is about the same as the water temperature and there is no solar radiation adding heat to the system. In the real world, it will be somewhat less effective than that.

However, running FT water though the copper pipe will kill your fish

Thanks gunagulla had no idea running FT water through copper pipes would kill fish

Thanks will keep it in mind, though probably a bit of effort to get them here seeming I only wanted a smaller number to supplement my summer stock. Hopefully will find some this friday when i am in town.

A method i have seen to cool aquaculture water for coral farms is to use geothermal. A poly pipe is buried along a long trench. You pump water through this pipe to cool it to the natural below ground temperature. You can then use a heat ex-changer to cool the water of the system. I would imagine with a AP system you could get away with just circulating system water through the pipe 24/7. Should give a more stable year round temp.

We have some warm weather predicted for this weekend so I will put up some shadecloth over the tanks and lower the water level in the growbeds a few centimetres. Just staving off the inevitable for as long as possible.

I may have to go back to the drawing board after today.I had plans to take twenty out during the month so that I would be down to ten big ones and then put them in the outside tank for the warm weather.How ever it appears that if the temperature comes up suddenly they can't take it either.I had been in Perth all day and when I got home most of them were swimming around on top so I took ten out and cleaned them and have my fingers crossed that the others will be OK.I was surprised to find that a lot of them are close to 900 grams so that loads the system up more.The temperature was only 20 c,I have had it up to 24 before with no problems.The temperature has come up eight degrees in less than a week.

What's your temp sitting at?

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It was a warm day, I think my big below ground sump helps keep it stable temp hit 17.5C but is back to 16 this morning. Trout are still feeding strong. Though started to take the odd one out about ten mins before lunch time They are tasty little suckers.

I also had the shade cloth up in preparation for the hot day.

The last few days at around 4.30pm its been 15 to 16c.