Backyard Aquaponics
A place to discuss aquaponics

Greetings all,

I've been reading this forum for a couple years now, filling my head with ideas and filling my yard with various parts and pieces of a fairly ambitious project.

Construction is currently scheduled for early spring = April (although the schedule in my head seems to change on a whim).

Planning on a sunken greenhouse with a CHIFT PIST flood & drain system - easily convertible to constant flood if desired.

So far I've accumulated:

(1) 1200L IBC - planned fish tank
(3) 1000L IBC - to be cut in half for grow beds
(1) 4000L HDPE tank - to be buried as sump tank.

I know, the 4000L is a huge sump, but I expect it will add stability due to the large volume of water (& thermal mass) in the system, and allow for future expansion (which by reading this forum, seems inevitable), and it was free.

I've also gathered a nice amount of tempered glass panels (old door panes from a local retailer) to use as the front and roof of my greenhouse.

The required plumbing will be no problem. I have a couple years on the tools under my belt, and currently sell all the required material (we specialize in plastic piping for industrial and aquaculture users). So I'd be willing to bet I can get a pretty good deal on it too.

I'm having a problem sourcing a suitable grow bed material. Gravel would be my first choice (due to cost), but the local aggregate suppliers provide primarily limestone. I'm looking into a couple of the smaller private gravel pits with high hopes. Hydroton is still an option, although 3000L of hydroton will be quite cost prohibitive.

I expect the vegetables in the system will vary by season, but I'm planning on growing trout year round if possible.

Although it remains to be seen how the system will operate, I anticipate a couple concerns with temperature control:

Summer: 30C is common, although not for extended periods. Temps will be higher in greenhouse conditions. Too hot for trout. I have a very good source of cold groundwater (8 to 10 C) and could do regular water changes to keep the temps down, using the excess water for the soil garden of course. How often and how much water can I change without robbing the plants of nutrients?

Winter: Week long spells of -10 to -15 are fairly common here, with occasional drops to -20 or even -30 (although those aren't too common). I'm willing to add supplemental heat to the greenhouse as I expect some will be required. I can plant hardy vegetables that just need to be above freezing, and I know the trout will be happy as long as the water's not frozen. My concern is the bacteria colony. I've read they become virtually inactive below 8 or 9 C, but does there come a point where I lose them altogether and need to cycle again?

I'd like to thank you all for the inspiration and information. As I mentioned, I've been reading this forum for a couple years, have read through and absorbed most of the technical info available here, and have closely followed several of the build threads. My real inspiration has come from Zsazsa. Thank you for being so thorough in documenting your build and your system's operation through all of it's ups and downs.

Well, that's my plan. Please feel free to comment and offer advise to keep me on the straight and narrow. All advise will be taken into consideration, and then ignored when my wife tells me how she wants it done.

Looking forward to finally getting this underway.


Cheers,

Brian

Welcome pleased to see that you are planning well. Why not use the 4000 lt as your FT and the 1200 lt as your sump.

Welcome Brian

I really feel for you guys with extreme temp changes. There are a few members around with your types of climate and they seem to manage through the extreme cold so its definately doable. The greenhouse will help a lot.

There's a couple reasons for not using the 4000L as the fish tank.

First of all - I would fill it with fish....and I don't have the growbed capacity to filter it. And to my understanding, I need to circulate the fish tank volume every hour, not the system volume. 1200 lt per hour is a much more reasonable flow rate.

Second - the 4000L is much more suitable for bury than an IBC. It's a HDPE septic tank. Don't worry, it's new, and made from potable resin. It had a defect, so the manufacturer gave a credit to the wholesaler. The wholesaler (me), in turn, had to agree that it would never be installed for its' intended purpose. I'll take care of that.

No problems then, good score for your side, thanks

Haha that means you can't pee in it to help cycling.

What's your inground temp ie if you bury the septic and filled it with water and didn't pump it round what would be the temp?
The change the FT volume every hour is a generalisation not a hard and fast rule and relates to stocking levels. you would have as much O2 in a 4000l tank using the same pump that would change the 1200l every hour (there may be problem if the 4000l is tall and thin).

Ground temps here are pretty stable around 8C once you get to 2m deep. I'm kind of hoping the large volume of water underground will stabilize the temp of the system through the summer and winter, almost a mini geothermal system.

I'm not sure what the shape of the tank would have to do with O2 levels (except maybe the surface area exposed would absorb oxygen?). Anyway, tall and skinny is not a concern. Tank is pretty short and fat.

There's two 20" openings on top. So yes, I can pee in it. Big volume though....might take more than a six pack to cycle it.

Most of the 02 exchange in a FT occurs at the water air interface and some pumps have difficulty at depths.
BTW nice tank only problems I could see with it is if the reinforcing ribs extend across the bottom.
I often sound like a pessimist but I always look for problems first and try to work round them.
I would put a lot of thought into the greenhouse they can heat up more than you think and can dump heat very quickly.

i look forward to hearing your progress, it being nearly the end of april. Also from NB, and looking to see how people in a similar climate are making out.

i look forward to hearing your progress, it being nearly the end of april. Also from NB, and looking to see how people in a similar climate are making out.