Backyard Aquaponics
A place to discuss aquaponics

I watched a clip on a guy building a solar powered water heater for his unit? But the sun don’t come out at night when your fish need the heat? There are lots of ideas out there, I am just going to look at a few more till I find one that works, I have a bit of spare time on my hands, I have lots of ideas, I am quite happy just to bring the warm weather fish indoors for a few months, its quite relaxing watching the fish swimming around, well more relaxing than watching the cat stare at them!

Fish aside for a moment, one factor often overlooked in winter aquaponics is the nitrifying bacteria. If it gets too cold, they can be impaired from doing their job:


The temperature for optimum growth of nitrifying bacteria is between 77-86° F (25-30° C).

Growth rate is decreased by 50% at 64° F (18° C).

Growth rate is decreased by 75% at 46-50° F.

No activity will occur at 39° F (4° C)

Nitrifying bacteria will die at 32° F (0° C).

Nitrifying bacteria will die at 120° F (49° C)

Nitrobacter is less tolerant of low temperatures than Nitrosomonas. In cold water systems, care must be taken to monitor the accumulation of nitrites.
http://www.bioconlabs.com/nitribactfacts.html

I used to live by the coast, and my AP systems thrived all year round with the moderate temps. Now I'm living inland with severe frosts, and am having troubles with vegie growth rates over winter in my AP systems - they slow right down over winter whilst the soil beds kick on. The fish are still feeding.

My water temps get down to about 1-4 deg c.

I'm left suspecting a die down of my beneficial bacteria. Am I wrong on this?

I don’t have a temperature gage on my grow beds, but my sump tank is always 2deg lower than my FT, but I was thinking if we test the water that gives us the readings of nitrites ect, wouldn’t the bacteria also be in the water? So technically your whole system is a bio filter,

I already have an enclosure built for the compost. Am making a 100 ft coil of pex pipe wrapping it around a reinforcing screen like that seen in some of the Jean Pain videos. I want a continuous piece of pipe with no joints within the compost. No failure points.
I'll put on a small pump to circulate the water and see how this works out.
I have a friend that is a heating contractor and he has taken a real interest in capturing heat from compost and is advising me now.

Great link jono81 some interesting facts, thanks.

I'm going to jump in on this as i got my barra fry yesterday - they came at the right price but I'm having trouble keeping the water temp up - they were bred at 28c and its going to be cool and rainy later in the week. I just need a quick short term fix. I turn off the pumps at night - 1 just goes through a 60m coil of black poly in the sun, 1 does the growbeds. I've got a heavy silver tarp over the tank at night and a 300w heater and i lose about 2c overnight, which I make up easily on a warm sunny day - got the 2000l tub to 26c today (+7c over the warm part of the day), but a week or so of cool weather forcast has me worried. any suggestions welcome

Craig

Thought one of these might do for the short term

What about a thermosiphon style solar heater? You could run pipe on a roof if close by and use the sun

I brought a 300kw aquarium heater, ran it for 24 hours and got one degree temp rise, I put 3/5mm insulation around the fish tank and tarps on top of the fish tank and sump tank, temps were maintained longer and when the sun came out the grow beds kicked in, so I used my timers as to when to run the pump! At night 15 min per hour just to keep the water turning, during the heat of the day I now keep a constant flow from 7am till around 8pm, the water temp is staying better than before slower changes, not as rapid or as low? So there are many ways to alter temperatures, without spending to much money?

There are quite a few 'heating' threads that are worth having a look through. Unfortunately it's costly to heat and retain heat within an AP system. With the kind of temps your discussing you will need to look into an indoors system or a heated greenhouse, both of which have some downsides. I feel for those members living in cold climates.

Check Robs geodesic dome thread and Dave Donallys threads and there are a few others battling the cold. Also check some of the compost pile threads as I believe that method isn't very successful.

I think if you want to over winter barramundi in Perth it's best to use just recirculating aquaculture in a heavily insulated setup. 26 degs water temp in an aquaponics system in Perth will be very energy intensive.

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Its not not really over-wintering for me, rather than having the capacity to get the Barra early while holding on to most of my trout for as long as possible. I want to have my cake and eat it too. Today was a case in point, my two trout ponds hit 22c without help, while at the same time I was trying hard to get the barra pond up to 26-28 to help it over the coming cold days.

My Barra are at 25deg now outside its 7pm, I haven’t tried trout as yet? I did spend a bit of time deciding on where my tanks would go, not that I had much off a choice! Small back yard, but the optimum sunlight was factored in before final placement, and the temperature placement between the sump tank and fish tank, until today my ST was always 3deg less? I am using a split flow system, so I can alter the flow rates at will, I am still experimenting on how? It all works. But when I first started this system the temps were 8deg and 12deg in the FT,I take it the sump tank has heated the ground around it, as it is half submerged? So in a way that would be thermal power?

Oh well still a lot to workout,

Well, its Feb 15, my greenhouse temperature at 10pm is 18 degrees F. With the windchill outside it is -12F and is expected to be that cold for the week.
I made the tank heater in the youtube video using a hot water tank heater. I used it all through December and my electric bill nearly doubled for the month. Not the best idea.
I shut the heat down the first week of January. The fish eventually died off. I keep scooping dead fish out of the tank so that their carcasses don't poison the water. I will be better prepared next winter, I will have cold weather fish and warm weather fish. I have big enough fish tanks in doors to do it. Nothing has frozen yet, I keep the water moving to prevent freezing. We have harvested the last of the spinach and kale and I am preparing for longer warmer days.

I think I will have a woodstove solution next winter.

Which you tube video are you referring to