Backyard Aquaponics
A place to discuss aquaponics

Hiya dangus, I did write a detailed reply regarding the shed but it disappeared so I took it to be a sign.
Briefly,
Personally I wouldn't put the ft into a small shed. Large shed maybe.
Temp swings being the main factor.
In the shade or under an open cover would be a wiser option IMO.

Hey skeggley sorry if I missed your reply, no idea what happed there? Now wishing I got to read it. So having the FT in shed would make water temps fluctuate more than being outside? Which would add to stress on the fish?
I thought the shed may increase water temp but given that silver perch can handle up to 35c I thought I would be safe.
If so then a basic setup as I have shown in my last Google map plan should do?
Maybe still pave and border with bessa blocks in case of future GH or not worry about that either?
My original plan was to be able to grow year round by stabilizing temps somewhat.

The best way to stabilise temps is using the waters thermal mass. The more water in the system the more stable the temps. I have two systems, one with 1000l water the other with 6000l. Both systems in roughly the same area and the larger sys generally varies by a degree opposed to the smaller with 3 degree fluctuations, not that this appears to stress the fish.
Having said that it is your gb's that are your heat exchangers so things like flood depth, gb depth, area of media exposed to direct sun are the main contributors of heat gain/loss.
Insulating as much exposed parts of the system, shading and earth coupling will help.
Silver perch are a great idea due to their temperature range and hardiness.
Hope this helps.

[quote="dangus"]
I thought the shed may increase water temp but given that silver perch can handle up to 35c I thought I would be safe.


Dangus if the outside air temperature was up around 40°c - 42°c the temperature inside the shed would be anything up to 50°c or above and that sort of temperature would soon raise your water temperature and kill your fish.

Early in the year here in Melbourne we had 4 consecutive days of 42°c and above and I added 3 x 3 litre milk bottles of ice TWICE in an hour to my fish tank and it made very little difference to the water temperature.

I covered the FT and GB's with shade cloth and ran fans on both the FT and one directly on the water surface and that only lowered the temperature slightly, the only way I could make any difference was to run the hose in the sump.

That way I was able too keep the water temperature around 11°c below the ambient temperature.

If you opened opposite sides of the shed and got some cross flow air flowing through like they do in their houses in Asia that might help keep the temperature down.

The temps are a bit of concern for me too Dangus, I've planned to bury 4000ltrs worth of sump to help a little by bringing some stability. Believe it or not it can get chilly in Central Thailand to come December, same principle at play, 4000kgs of buffering, plus the 4000kgs in my FTs too.
It's all going to be in an open sided shed, I'll put up some shade cloth and grow some AP trees on the outside to help cool things down.

Your design looks good, I dare say when building you'll have some flashes of inspiration and modify a thing or two here and there.
Even taking my time away at work into consideration these projects take longer than you think, those IBC's aren't the easist things to cut either.

She'll be right though!

My hottest day here this year was 41.8C (measured with the Davis weather station about 50m from the AP system), and the water only got to 26.5C. Buried FT and ST, plus stopping the sun shining onto most of the black GBs with Air-cell, and polyester insulation stopping it shining on most of the GB media gave me the >15C differential. I wasn't adding any ice then, as the Murray Cod that I'd added a day earlier were fine at that temperature.

Its 19deg outside its been raining all night and day but my FT20.4 ST18.3 don’t care? Sump tank was overflowing earlier as I have an overflow pipe fitted. Sorry new guy that thinks ahead here! It has taken weeks for my water to get up to temp, this is a half submerged sump tank no insulation on the sump tank, the fish tank has minimal insulation 5mm thick! Which is floating floor underlay, its nearly 5pm, the temps haven’t changed by more than one degree all day since 6am when I fed the fish, a large volume of water takes longer to change and that change happens slowly,

As for the ice milk containers, I have used this for years in aquariums but smaller systems and smaller containers, as I said before, the idea is not to cool the whole system down? Its to provide a comfort zone for the fish only, we put electric heaters in water why not put an enclosed piece of ice to cool a small area? I used the example of turning a fan on as that is what we do to cool down when hot, these days I just turn on the ducted air-con,

I think we should all start thinking more positive on how someone can get better outcomes rather than think of all the negatives?

dangus, I placed my system, not that I had that much off a choice! Where the fish tank had less direct sunlight, and the grow beds would have the most, I am still thinking off a cover, but the wind we get here overnight is like a cyclone going through!

All the best on how you work it out for yourself as we all do what we want in the end,

Thanks, its perfectly clear now the risk I have having the FT in the shed, and makes perfect sense that increased temps in the shed will rise water temps, I don't want to create a system where I am required to be at attention to every detail, every day.

I understand that the larger the total mass of water in the system the less effect on fluctuations.
If my ST and FT were buried I can understand how that would act as a heat sink and help stabilize temps.
But that's unfortunately not an option for me due to the worry of my lease terms and the work to leave the area as I
found it.

There is a slight gradient from left of the backyard from the house to the right. So now makes sense to position the FT to the Left of the system to aid gravity feed to the GB's from the SLO's.

The FT will be covered by a shade structure of some sort?

My next biggest decision now is whether I should be still thinking of the Sproutwell 6m x 3m Greenhouse http://www.sproutwellgreenhouses.com.au ... model.html
or should I now look at a pagola type cover like Faye's system? Since now I am not trying to raise water temps to accomadate Jade Perch?

Dangus, one thing you may be able to conider is not fully burying your sumps, but hilling them in? If you can dig them down just a little (even just 5-10 cm, as long as you have the supports off the bottom of the IBC to allow ground contact.) and hill that same soil up the sides of the bin, it will help. If you can insulate the top of the hill/soil alongside the tote, that will help a bunch more. Perhaps some scrap styrofoam below the pavers alongside the sumps? Come to think of it, if you place the sumps before you place the pavers, you gain another 5cm of buried depth. I'm not familiar with australian building, but some areas use the horizontal foam insulation around footings as frost protection, if you want to google the idea for reference.

In the hot weather leave the doors of the shed open if you can. The whirlybird will help but I dont think that it will be enough. As the water gets really warm it will hold less oxygen. Put a cover on the fish tank. Not so much to discourage evaporation but more to keep the fish from jumping out. Some chicken wire fencing will work for that. In warm weather I evaporate about 30L per week. Fall is here and time will tell how much evaporation occurs during cooler weather. I expect evaporation to continue or increase as the volume of vegetation increases. Plant leaves evaporate water.

I have a 1250L IBC fish tank with a 1050L sump. There is a 12 by 24 inch opening cut in the top of the fish tank between the two top cross bars (I wanted to maintain the strength). I still find a fish on the ground once in a while, jumping for bugs or whatever.

viewtopic.php?f=18&t=22925&p=479528#p479528

Thanks for the reply and now can see that having the FT in the shed is not the go. I definitely don't want to be in a situation where I go out early in the day then discover that I need to rush home and open the shed because its too hot. Also I can see that the increased temps will cause less oxygen in the water.

I want to make a start but also want to have the complete plan down on paper so I don't make any regrettable mistakes.

I am now very undecided should between a GH http://www.sproutwellgreenhouses.com.au ... model.html
or the pergola such as in Faye's System viewtopic.php?f=18&t=1622&p=477887&hilit=fayes+system#p477887

My plan is to be able to grow year round but finding it hard to work out which direction is the best?
There isn't much info on AP GH's in sydney, maybe our climate is similar to W.A?

I wish I could bury the ST's but again the problem of my lease terms and refilling the holes if I had to move make it unfeasible.

Dangus, I wrote you a full response, but it seems to have gotten lost, maybe in the moderation process. I'll try to replicate it, in point form. All of these topics relate primarily to the sumps, although they may be relevant to the FT as well.

-any ground contact you can achieve will help. Make sure you remove the frame (feet) from the base of the IBC, and try to bed it to the ground.
-even if only five cm of dirt were dug out under the ibc to bed it as above, this dirt would then form a 'hill' along the sides of the tote.
-the pavers should be laid after the totes are in place as these will give you another 5cm or so of buried surface.
-I'd try to lay some (scrap?) styrofoam (or a couple layers of old carpet)flat on top of the hilled soil out the sides of the totes (under the pavers). This may help force the thermal coupling to be through the tote, and not through the pavers. This is sometimes done as frost protection for footings.
I realise that water is very limited for most of you, but evaporative cooling is very effective. If you run some or all of your fishtank return down a large suspended scotchbrite / furnace filter pad, I bet you could get a significant cooling effect, albielt by incurring a (fairly significant) water loss. Note that this can backfire if the air is much warmer than the water, so may be most effective at night. However, it will also cool the air in an enlosed space, like a shed.

I hope some of this may help. I live in a cool climate, and my thoughts are normally directed to capturing and retaining heat, not removing it.

For fun, I looked up the numbers. (been awhile since I worked with them) Every liter of water evaporated would provide 2135 btu of cooling, some to the water, some to the air. Put differently, evaporating one liter of water would drop the temperature of 540l of water by 1 degree, minus the amount lost to cooling the air. I know I saw one thread where someone was spraying a shadecloth cover for cooling, perhaps others have some experience to share as well.

Not taking into account the energy being continually added to the system by the ambient heat!

2270kJ to evaporate 1 litre

2270kJ/4.18kJ/kg (Specific Heat) cools ~540l by one degree, ignoring air cooling, but conductivity from everything in contact with the water, plus any direct radiation is always heating it up, so you will evaporate a lot more, for a lot less cooling than you'd like. Excluding heating is the easiest way to keep it cool.

As much shade and insulation as you can apply, then add more insulation, and as GM says- as much contact with the ground as you can manage. With my reasonably large FT and ST buried, I still sometimes see up to 4C temperature range in a day- that's over 25kWh of energy being added to the system and of course a similar amount is lost overnight. In my system at the moment, most of that energy exchange is happening via the 9 GBs.

Dangus,

If I may,

I love your project, outstanding, i have subscribed to this post.

But if i may, some small suggestions,

1. Might i suggest that you consider a constant flood configuration.
I believe that in a system of this size, it will offer you far more control over your water levels than messing around with a multi-sump arrangement, way to many moving parts and potential fail points.

2. If you were to consider a CF configuration, then you would need only to calculate the amount of water above the stand pipe height across all 12 beds, allow a 200-250(ish)ltr fudge factor and have only two sumps sized accordingly, one for each row of GB's. That way, should the pump fail, a siphon block up or fail or any number of other issues arise the water above the stand pipe is the only water to drain out. Water is still left below the air root layer and media wont quickly dry out.

3. My reasons for this are reasonable simple, if you look at all the large or commercial systems, they are (to my knowledge) all deep water/raft systems, because it is more feasible and less moving parts to fail (amongst other benefits outside the scope of this post) so irrespective of the media in your beds, a CF configuration applies that same common sense.

I hope i have made sense, but in a system that size, the less moving parts and sumps here there and everywhere all linked and all the plumbings and fittings (cost) involve, the better.

I would suggest you link all the beds to a 100mm (minimum) common drain and run that drain back to just one sump per row.

I hope i haven't added to your confusion, i can do a quick sketch if you like, and i look forward to seeing this built!

Regards to you