Backyard Aquaponics
A place to discuss aquaponics

Okay - despite me having 350 watts of heating going in my tank all the time now, having polystyrene around the outside sump for insulation (fish tank is in the shed and has insulation on the top), the temps in the tank are continuing to drop, to the extent that today the fish did not eat their single daily feed as the temps were still below what they like to feed at (at 11am).

The question is what I do from here. I am not certain exactly how many Barra I have left, given that a few have died over time and they are cannabalistic - but I'd have more than 80 for sure.

The fish are an advanced size and ready to explode at the right temps. The average size would be over 200 grams I would suppose, with quite a few of the fish being over 300 grams.

Options left to me to keep the heat in include providing more biofiltration in the shed so that the pumps are turned off earlier at night (currently they go off at 8pm - or is it 7pm :-/), adding extra insulation to the inside tank, setting up a quick and temporary solar heating system using the pool heating tubing that I have (would have to be a bit of a bodge job at this stage) and/or setting up a quick and nasty greenhouse (just some of the 32mm PVC Pipe I have with plastic over the top) to keep the beds a little bit warmer in the day and at night.

I suspect that the temperature losses are attributable to several things - all of which are related to the fact that it is quite cold where I live at night (will get some sub zero nights before winter is over). These things are:

1. Eventhough the beds are offline at night, I guess the media would get quite cold at night and transfer some of this in the morning when the beds come on again.

2. The shed is not insulated and the insulation I have added to the tank itself is minimal at this stage. Biggest problem I see though with keeping the tank warm regardless of insulation is that at night I have to pump quite a bit of air into the tank to keep the O2 while the pumps are not on. This air in the shed gets quite cold as the night goes on and would have to transfer cold/take heat out of the tank as a result.

3. I guess that despite the insulation I've added to the sump - the water that sits in that through the night woudl still get a bit cold. I probably need to add some more insulation where the pipes enter the sump - as there are some gaps there.

Selling the Barra may be an option. I'd probably only look for $3 each for them - which is cheap given their size and would not even cover the expense of buying the tiny 25mm fish ($1), the feed and the power used to date. I started with these fish in late October and they were tiny. Ideally I'd have grown them out in summer/autumn, but I was just not setup well enough to feed them at optimum rate.

If it's possible to keep them without the costs running too high (heating etc) I would do so.

Imagine if they got through winter alright, their growth would awesome and you would have tough barra.

my 2c

If you sell them, let them die, or give them to Les, you will never see them again. I'd really like to see you nurse them through the winter and then grow out some really big fis in summer (but that's easy for me to say. If it was me I'd probably SELL them to Les)

oersonally, I would keep them VB. Another couple of months and you are in. Those fish will be enormous by the end of next summer, and will priovide muchos nutrients for the many growbeds which you will no doubt add before then Crank up the heaters! And if worst comes to worst, eat them. 300 grams ain't a bad size. We shouldn't be obsessed with eating the fish only if they are big, when getting them to that size may not be practical (even though we know it is possible)

Now are you confused?

I'll have to look back through the thread and check system but will add what i can now.

Ok , beds are sucking the life- heat out of your water .....,, do you start slow ( pump a little ) and slowly increase pump time? This will help even out the temp changes.
You DEFINATELY need to cover the grow-beds with something clear ..... even in winter they will gain a BIG dose of warmth during the day..

Good insulation ( as you can ) is needed ,, as with houses start from the top down ,, roof most important ,, walls next then floor.

Mount your air-pump as close to the top and near the warm fish tank ,, hopefully it will then suck in air several degrees warmer than it is now.

300 watts is not much ,, are you running it on off-peak power???
On off-peak you get about 800 watts for peak 300 watt cost.

In my area temps nearly NEVER below 6 C ,, but I still plan a commercial grade hot-house material for covering grow beds ,, tank fully insulated with quality insulation ( also in an insulated shed and bio-filter in shed ). Sump in warm shed .....,,NOT buried.
And 900 watts of available OFF-PEAK heating.

I hope you keep them ,, selfish reasons I guess,, I'm learning a lot from the difficulties your having
You gain a mere $3 a fish if you sell ,, you gain a LOT of learning from trying to make it through to Spring. If you can Barra thru winter ,, the world is your oyster:) ,, Jades SP etc will be easy.
If you have the time to twice check daily ,, then the fish that die from cold will definately be safe to eat ..... 300 gramme ..... under the griller.

Ultimately your fish your decision.

VB, can you delay the morning pumping until it is a bit warmer, my trout go from 7pm through to 830 am before the pumps starts again.

Use a spare water pump, instead of an air pump to aerate the water. I have gained over 5 deg c in 4 days

my idea would be to take all of the fish to les and let him nurse them over the winter and then take half of them back after the worst of the cold is over. THis means

A) les will have fish that he needs to eat now and may invite us over for lunch
B) you can still have the pleasure of being only 1 of 2 people in the queensland AP community to grow out barra this season, and the fish are definately worth it.
C) les will feel he has been done right with his barra purchase.
D) will not cost you much to have them through to winter

Just an idea, Nick

But what about my learnering
Damn ,, I really wanted to see how much more heat he could get with my ideas$#@@&&^%^%.

Actually the idea of taking them over to Les is a possible solution... given he has both his tank and growbeds inside a greenhouse....

What temps are you running Les.... you could always borrow the heater as well ...

... and some of VB's polystyrene insulation... think he should have some to spare

No clue how your plumbing is set up VB, but is it at all possible to use the sump pump in the morning to circulate water through the pool heating tubing (will it pump to the roof of your shed?) back to the sump via the growbeds. When its warmed up a bit switch it back to the FT?

Would require manual intervention...buggered on a cloudy day...still have to heat that FT at night $$$

Thanks everybody. Let me clarify a thing or 2:

1. The Les option has been added by some smartarse moderator.
2. Les never bought any Barra. The losses were sustained by me and me alone. It is just a running joke between us.
3. The heaters are on all day and are on Peak power. I do not have another service to the shed.
4. Insulating the shed and adding the pool solar heating stuff to the roof of the shed is all in the plans, but just will not be happening in time to deal with the current dilemma.
5. Having the sump in the shed is not an option due to the height it needs to be at (which is why I have dug it in. And no I will not cut a hole in the concrete.
6. The temps Les is able to maintain in winter, while lots better than mine, will also be unsuitable for Barra.

Where to from here. During the week I'll give some thought to whether I can easily and without too much expense add a temporary (and I mean dodgy, short term crapy thing) lean too or or hoop greenhouse over my beds (with single layer of film) and in a way that I can still get in and out to my beds. I have the materials other than the plastic, so now to find some fairly cheap plastic.

Secondly I'll give some further thought to hooking up some of the solar tubing . I'll probably just lie it on the ground as I am not setup to pump to heights at this stage - and my shed is high (over 3.5 metres just at guttering level).

All comments and advice appreciated. I've not ruled out selling the fish though, because the costs I may have to put into heating to get them through may just not add up to a reasonable thing - particularly if I end up killing them anyway.

for the fairly chap plastic (it's just for a roof for a season right? ) try clear builder's plastic from somewhere like Blackwoods $30? for a 100m roll? at about 1.8m wide? It's not clear-clear, but translucent-clear IYKWIM

I wonder if that will even last the 3 - 31/2 months it needs. I have used that sort of stuff over my tank when it was outside and it degrades very quicly in the full sun and heat.

we're using it as the shower cap over the fish tank for winter. It's the same pieces as last year. Not in full sun admittedly, but still okay.

300Watts! I have that in my 200L tank. More Watts! Heat that water up. Insulate the growbeds, Black polly wher you can.


My 2cents worth.