Backyard Aquaponics
A place to discuss aquaponics

Hi all

Firstly, really appreciate all the helpful advice provided through this forum. As a bit of background, at the end of last year I decided I needed a hobby and happened across the concept of aquaculture by chance.

I set up the basic IBC setup (as per the IBC of Aquaponics instructions) and have had a reasonable amount of veggies and the small number of trout I purchased (despite some deaths) seem now be growing nicely.

I'm enjoying it that much that I'm keen to build a bigger system. Hopefully it'll be completed in time for silver perch fingerlings in a couple of months. Not too confident of that goal as it has been wet, cold and miserable lately and with two wonderful little kids, free time is in short supply! But I'll try.

I've had a few goes at Sketchup but failed miserably so used publisher instead to provide a top-down view of the proposed system. The existing IBC system and raised garden bed (neither included in picture) take up the rest of the space between the cubby, shed and back/side fences.



I intend to start with one IBC fish tank with just the very top cut off (so 800-900l of water for between 40-50 fish). There is room / plans to add an second IBC FT later.

I plan to use an SLO to run water to the growbeds (sadly the ground slopes down a bit so will have to raise the FT to get the SLO to run). The growbeds (x4) will be cut down IBCs and drain to a full IBC sump partially buried under the growbeds and then pumped back to the FT. Will probably add overflow pipes to both FT and GBs.

I intend to run constant flood so I know a full IBC sump is not critical but decided to go with it for system stability, possible expansion (not too big as limited space) and general experimentation (trying flood and drain at some point). The growbeds will be filled with media so no current plans to include a RFF (although I have a 220l olive barrel that could have been used).

I'm hoping the GBs will look presentable so, while I'm not the best woodworker, I am going to take inspiration from guitarwes and hoping to model my GB setup on his. http://backyardaquaponics.com/forum/viewtopic.php?f=18&t=21386&start=15#p454161

So... I have the broad plan, now I'd like to throw out some technical questions for advice
Q1 Any general comments / advice on my plan?

Q2 Is 50mm the right size for an SLO? I plan to use 25mm PVC for distributing water around the GB (rather than have a single inlet per bed) so where are the best points(s) to step down in pipe size? I expect only a very slight downward angle in the piping from FT-SLO to GB.

Q3 Where the SLO exits the FT I was planning to put a 'T-piece' with one side closed off to allow me to feed in the second SLO from the future second FT. Does this effect the size of pipe needed to travel water from both FTs to the GBs? I haven't got a handle on how fast an SLO takes water out.

I think that's it for now but sure more questions will come! Plus grumbling about the digging....

Lunch:

So... I have the broad plan, now I'd like to throw out some technical questions for advice
Q1 Any general comments / advice on my plan?

On your plan the FT is quite a distance from your GB's and you mention that you expect to use only a very slight downward angle in the piping from FT-SLO to GB's. I see flow problems and solids build up over such a long distance without a decent fall.

Q2 Is 50mm the right size for an SLO? I plan to use 25mm PVC for distributing water around the GB (rather than have a single inlet per bed) so where are the best points(s) to step down in pipe size? I expect only a very slight downward angle in the piping from FT-SLO to GB.

I would make the actual SLO it's self out 90mm, if you can achieve a decent fall from the FT to the GB's, then the use 50mm pipe from the outside of FT down to your 25mm GB distribution would be OK, I would prefer to use 90mm but 50mm would just scrape in (not the ideal). If you cannot get a decent fall I would continue from your SLO in 90mm pipe all the way to the GB's and avoid any flow problems. In my own system I used 50mm from the FT to the GB's and have regretted it ever since. Like myself people don't see or plan for the future expansion and believe me that will occur.

Q3 Where the SLO exits the FT I was planning to put a 'T-piece' with one side closed off to allow me to feed in the second SLO from the future second FT. Does this effect the size of pipe needed to travel water from both FTs to the GBs? I haven't got a handle on how fast an SLO takes water out.

Again running 90mm pipe would suit using a "T" better than 50mm would. On how fast the water flows from the SLO, it leaves the tank at the same velocity it's pumped in. Think of a tank without a SLO, just a plain vessel with water being pumped in, when it was full it would overflow from the sides of the tank, the SLO is in fact just an overflow. The only difference is that it overflows from the bottom of the tank not the top of the tank as a normal overflow would.

Overflowing from the bottom it will drag the fish solids from the bottom the tank against overflowing at the top of the tank where it would achieve very little in the way of solids removal. Some people think that it's suction, it's not suction, it just the flow of water leaving the tank by the SLO at the rate it's pumped in. If the water is pumped in any faster than the SLO can handle it will overflow the tank, so there's no magic it's just an overflow.

The SLO will need a "T" at the top to stop any siphoning and it's advisable to run a normal overflow from the FT back to the sump.

Thanks for the advice joblow! Much appreciated.

I don't want to get solids building up and clogging the system so will try to raise the FT higher than originally planned and lower the GBs but still high enough that the dog won't jump in them! (shame the slope of the ground is the wrong way...)

Finally got the pictures resized so they'll appear here. This is where the GBs will be with the sump part buried just left of the window.



This image shows where the FT will be (to the right of this picture - up against the back of cubby) and the path the PVC will take to the end of the garage.



Thanks also for the SLO advice. Will definitely use 90mm pipe. Am also going to try to incorporate the advice provided by Stuart in the FT design thread.

Decent weather today... might start digging!

Dug about 50cm today for the sump. Made better progress than I thought. Hole should be finished next weekend (weather / other distractions allowing).

Probably too late as you have started digging your hole for the sump, but could you not relocate it closer to your fish tanks?

Hi arbe.

A fair question I spent a fair bit of time on that! Ideally, yes, the sump would have been around the back of the cubby with the FT but the space is really quite limited. I wasn't confident of there being enough room without the FT(s) needing to almost sit directly over the top of the sump and then wasn't sure how I'd be able to safely suspend the FTs in that scenario.

Edit: Need to remeasure but I think the horizontal distance from sump back to FT will be around 3 metres. Compare to my diagram, the sump is pretty close to the left corner of the shed - have left just enough 'safe' distance for the left side wooden posts that will support the GBs (plan is posts either end and also in middle).

you could SLO from FT into the sump then pump from sump into GB and FT that way use the natural fall from GB back to the Sump.