Backyard Aquaponics
A place to discuss aquaponics

So it took quite a bit longer to clean out the fish tank than I thought, not to mention work keeps getting in the way (thinking retirement sounds good, but wait...I need the cash to fund this ). I had a pallet rack lying around so I'm going to modify that to use as a gb base. Holes are now dug, rio is in and two have been concreted . Next up is a crap load of grinding and welding. Hopefully by the end of the weekend it will be fixed in place.

Growbed site fully prepped and awaiting the base framework. VERY glad to see the end of concreting!

Yay progress! It's a bugger when other things get in the way

Had a day off so got stuck into it this morning. Got the pallet rack chopped, feet cut and welded on, assembled in position and dynabolted down. I feel that I may have over engineered it a bit but hey who cares .
Ordered my uniseals yesterday from Rob so they should arrive in the next week and I can get stuck into the plumbing.

Overengineered is a heck of a lot better than underengineered!

Faaarrrt I those the northern hemisphere guys had guts building inside systems but dont envy you on that slope. One positive is that if it does ever fall over, you wont be picking up the pieces, they will be in your neighbours or the creek.

Enjoying watching your progress

So I have a bit of a design question...
From the FT I have a 40mm SLO that drops into a 50mm drain which then feeds via gravity to my GB and here's the question:
How do I get from a 50mm pipe down to 32-25mm that will empty into my GB? Where am I best to do this? Will this create too much restriction in my flow?
All sizing is subject to change as I am still working all this out.

Bump

My piping *to* my growbeds is all flexible tubing, but my piping *from* the growbeds is PVC... I have smallish pipes from the siphons that lead into a larger drain pipe via T joints where the top of the T is the size of the bigger drain and the stem of the T is the smaller size. The end one goes through a couple of reducers. Stuffed if I can remember the sizes off the top of my head, though, and since I'm about to go to bed and it's freezing cold out there I'm not gonna look now! *ahem* anyway, that might work. If you've only got the one GB though, I wouldn't bother sizing it down.

Thanks Mel, I enjoy the fact that I can pretty much do what I want but at the same time it would be nice to have some sort of guide rather than the plan in my head that is constantly changing

It would help, hey?

Expanding on my answer now that I'm awake: Like I said, if you only have one growbed I wouldn't bother sizing it down or putting any sort of restriction on the pipe (like a tap etc), because all the flow from your FT is going to need to go to the one place and restricting it has the potential to back your water up and overflow things. On the other hand, if you have multiple growbeds, it does make sense to narrow the supply pipes to them down from the 50mm drain, and also put some way to regulate/balance the flow in there, so that you don't have most of the water dumping out into the first one in line and not much reaching the last one. In that case I would keep the drain at 50mm all the way along, and just have the branches off it be whatever smaller size you end up deciding on. Also bear in mind that the branches off to the growbeds have to add up to the same capacity as the main drain, or that'll add a restriction that you don't want; and because you're dealing with area not diameter, you might need bigger branches than you think.

For example, your drain is 50mm, say you want two growbeds so there's two branches off it. The natural impulse for a lot of people (me too!) is to say "well 25mm is half of 50mm so two 25mm pipes will do it." Nope. A 50mm circle is nearly 20cm^2 in area. A 25mm circle is not quite 5cm^2 in area. So you would need four 25mm pipes to match the water flow capacity of one 50mm pipe. (And a 32mm circle is 8cm^2 in area, so you'd need three.)

And then you might as well go up one size to account for friction and things slowing down around corners.

I understand what your saying with area vs diameter, my thought process was that the pipe from the pump to the fish tank is only 25mm so I figured reducing to 32 or 25 mm from the 50mm drain shouldn't be an issue?. I have two grow beds at this stage so I'll prob put valves on to get even flow into them.

Your pump is going to be pushing water a heck of a lot harder than gravity can pull it. I've got a 25mm pipe from pump to FT as well, but my SLO and piping through to the sump are all 50mm and only barely handle it. Until I diverted some of the pump flow back into the sump, the water level in the FT was up over the top of the outlet pipe and nearly over the top of the open T at the top of the SLO.

Ah! I think you may have just saved me a HSM or two!

Hooray! Glad to help, and that's exactly what this forum is about.