Backyard Aquaponics
A place to discuss aquaponics

Hi from Canada. Great sight, great forum. I'm early on in doing my aquaponics homework, but I have one really pressing question I'd love to hear opinions on before I spend a lot of time digging into this, i hope it's not too ignorant...

I live in a moderate maritime climate on the west coast and am considering an aquaponics system for small scale commercial production of fresh salad greens and herbs. (i would just farm but the real estate trophy house market here has excluded new farmers from the land base)

Sustainability and economic viability are my two main concerns. I would like to use a herbivorous fish like tilapia for feed sustainability reasons, and with the new solar hot water systems available I think I could keep them going in a greenhouse pond all winter. But....I do have a short photoperiod and a lot of cloudy weather and the veggies are going to want supplemental lighting. I don't think I can live with that kind of energy input to my system...

so...

Has anyone here experimented with seasonal use of a system? Or does the time spent getting it to cycle, develop necessary bacterial communities, suffering initial fish loss, etc make a yearly shutdown too impractical / uneconomical??? Is there any way to put a system to 'sleep' without having to start from zero again?

thanks so much,

m.

Hi murrray and Welcome.

I have not used a seasonal system but you may not have to worry that much. How long will the low light period extend for? If you lower the water temperatures during this period the fish will slow down their eating and you will not need so much plant growth to take up the nirates. In addition to this you could experiment with a RSG (do a forum search ) filter which is used to gass off nitrates by using anaerobic bacteria.

Combination of these may allow you to keep the system running so you do not need to cycle up again. Basically it slows down to a pause. Here in South of Sydney my water temperatures are around 14C and my fish (silver perch) have nearly stopped feeding. I don't talapia becuase they are illegal where I live, but there is plenty of info around that will help you find the temp ranges that you could go down to.

hope thats a start and others can assist with more detail.

hey murray and hello to the wonderful word of aquaponics.

i hear you plea for better weather for ap. where i live it is the opposite: to hot during summers.

i am totally surprised that someone with more knowledge on this topic hasn’t replied yet.

the only thing that comes to my mind is to use warm loving fish and plants in summer.

IE: tilapia/catfish and tomatoes ect...

and for winter use cold loving plants and fish.

IE: trout/perch and peas ect...

i am sure that way better ideas will come with some of these geniuses on this board.

-df

and thank you for being concerned about energy usage, its a major problem in this country. i love it when people are doing better things for the future.

dank,,when did they take down the border??? Or are you doing a Brittney Spears,,,smiles mate.


Murray,,,soil temps are a really good indicator,,,basically mid-summer there in Canuk land,,,dig down half a meter and give a few temp readings.
The next question is if you would prefer warm water fish rather than cold-water species,..........,( I imagine salmon etc is fairly cheap there).

Did you want a bet on the womens 4 X 100 m relay at the Olympics??? Doesn't matter as long as a Commonwealth country wins:)

lol


skygazer and i replayed at the same time. i didn’t see it until now.


chappo in the USA it is really bad how people just don’t give a sh**. it really a big thong that they don’t care if there dead. so why care about the future. its really freeken crazy!!!

and Brittany Spears... well... her name is BS for a reason...

-DF

dank,,,,I've said it more than once here in this forum,,Australia needs GOOD immigrants,...............
I kid you not,,,similiar culture and ethics,,,wages and conditions are comparable,,,It wouldn't take you much long to speaker propa enlishh. Speeling may take a bit longer,,,we like a "u" in colour and a gh in tonight.
If the situation was reversed,I'd not think twice to immigrate to the US or Canada.

Something to keep as a reserve!!!

Thanks for the thoughts..

Maybe it's as simple as letting the fish cool and slow right down. (i'll search for that anaerobic bacteria filter thread). I wondered if I would lose the bacterial culture entirely on the plant side of the system if i stopped flooding, or whether it would survive a bit in the fish tank and recolonize quickly on re-start..?

Just to clarify...The light would be an issue for four or five months. I could certainly get something to grow in the greenhouse, but I don't think I could grow anything profitably without supplemental light and I don't want to go there. If the system isn't earning it's keep I can't afford to be here to take care of it daily, as I will need to go away to work.

Also if i could shut the plant side right down, I could get away with a much much less expensive greenhouse that I would just take down...otherwise I need to build something pretty substantial for the once-every-five years or so heavy wet snow event we get.

Trout or arctic char might make more sense but i think there can be real issues on the sustainability and safety of some of the commercial fish feed that gets used up there (hope that comment doesn't raise too much ire!) And in a recirculating system i'm afraid they'd get way too hot and low oxygen in the summer. So maybe tilapia depending on the solar hot water heating costs and minimum survival temps...Maybe just koi and sell them to the decorative fish pond people..koi overwinters here...

Don't have any soil temp data yet...december january are my coldest months with average lows -1 C and average highs of 5 c.

thanks,
m.

sorry, sarcasm about koi not obvious there and can't find the edit function...i won't be getting any 300 dollar fish to experiment with!

Yes you will need to keep flood / draining the grow beds because that is where the bulk of the bacteria are. 4 to 5 months is a fair while. Perhaps you would be best to grow out as much as you can over the good light period, the harvest 90% and just keep a few going at reduced temps over the low light period. You could take most of your grow beds offline with the reduced load, but keep a couple going so you can kick start again when the light improves. Or you can harvest ALL the Talipia then get a few Trout or arctic char over the cooler low light period to keep some bacteria in a couple of grow beds.

"Yes you will need to keep flood / draining the grow beds because that is where the bulk of the bacteria are."

Yeah, that's what I was afraid of. Which means I need a solid roof and I need to keep pipes from freezing on the cold nights. At which point it might make more sense to just plug the grow lights and heat in, pay the electricity bill and run it full time all winter long. Whether that's lower impact than importing our veggies from california, well who knows??? Would take some careful math to see if you'd break even as well...

thanks,m.

Hi Murray,
sorry, can't help out on the seasonal issue no problems with that here
welcome to the forum

+1 for skygazer

maybe a fluidised bed filter could replace the grow beds to keep a bacteria colony going with a few fish.

exactly,,,maybe a pool type sand-filter bu tfilled with bio-balls,,smallish and easy to keep warm,,lots of bacteria to re-seed grow beds come spring

it will work,
some how
some way it will.

say if you end up getting lighting for the winter, using high presser sodium or medial halide would be a good choice for the addition of heat. they get hot.

maybe with some air ducting the heat could be used efficiently.

-df

ps the two countries i would move to whould be Australia and Canada.