Backyard Aquaponics
A place to discuss aquaponics

Hi everyone! , just joined after hearing about aquaponics for the first time one week ago , I think that I understood the basic idea and tried to design a system that suits both my girlfriends aesthetic requirements, and my growing volume and efficiency desires. I will be building it out of earthbags and pond liner, with 2 pumps for redundancy. the fish tank will be 4000 liters, the grow bed about the same. I will additionally be building a greenhouse to keep it going year round ( I live in Israel, and the temperature is pretty hot 4/5 of the year, but up north in the winter occasionally it can be freezing) I plan to stock tilapia, and hopefully grow plenty of assorted veggies and with some luck, small fruit trees (the trees I will put in the in, hard to reach parts of the bed, to maximize space and to shade the fish). I don't think I've seen a system like this yet, and I was wondering what everyone thinks, and if it would work with just one bell siphon (the grow bed is quite large, but i would angle the far parts about 1-2 degrees sloped toward the siphon), also i would like to know what size plumbing would be required, and flow rate for everything to work smoothly, thanks in advance for all your help!
- Shuie

Welcome to the forum Shuie

Haven't checked the design yet but nice job with the rendering.

Cheers

Thanks Scotty!

Welcome.

Would definitely like to see the end results.

Sump will have to be in the region of 1500 litres?

have not calculated it yet, but now that youve mentioned 1500 sounds like a good starting point to test my calculations so thank you! , do you think the bell siphon will be able to handle the size of the growing bed?

The design looks great. I would consider splitting the growbed into 4. I think you will have a very hard time tuning a single siphon with that large a volume. The added benefit is that you can take individual growbeds offline for cleaning and maintenance without disrupting the whole system. It'll make plumbing more difficult but the benefits are worth it.

Also, consider slightly sloping the fish tank bottom so the solids can move to the SLO easier. It doesn't have to be much at all... maybe 5 degrees.

Thank you Chiumanfu! I appreciate the drawings I will definitely slope the fish tank, as to the plumbing, would making a single, extra large siphon make a difference? Since I will be making it from earthbags any extra plumbing would be a hugs hassle, (but I definitely trust the advice of the more experienced )

*huge hassle, not hugs hassle, though hugs are OK too

I can only speak to my experience. My current system has 3 growbeds 138cm x 114cm x 28cm = 440 liters each. My standpipes are 2.5cm and bells are 6cm and they work great.

My old system had one 250cm x 120cm (840L) growbed and it had to have a 5cm standpipe and 10cm bell before it would cycle correctly.

Your growbed is 4 times that size. Colum can probably comment on siphons for big growbeds.

OK thanks ! You've been very helpful

Interesting design. I'm going to suggest just going with Constant Flood but if you design it for either CF or siphons that would be great. The main difference being the size of the sump which is larger for siphons. Usually siphon systems have a small hole near the bottom of the standpipe which allows the grow bed to drain if there is a power outage. CF system standpipes don't usually have this so to switch you'd just remove the siphon and flip the standpipe so the small hole is near the top.

I think the flow from Fish Tank to grow bed to Sump and then pump back is a better way to go (this is how Chiumanfu shows the layout). I would also do the inflow like Chiumanfu but I would have 3 grow bed sections instead of 4. 1 section for each side because going around corners with the liner is more difficult. Since the beds are large a distribution grid for the inflow like BYAP uses, might be a good idea to get the solids and nutrients distributed evenly. I would have a single drain from each opposite the inflow.

Remember not to glue any pipes within the grow bed because you might need to take them apart for cleaning.

Thank you Scotty!

If I cut the FT and GB volume.by half, round the GB corners, and slope them all towards a single siphon would it be more practical? (I am not ignoring all of your great suggestions, but I am trying to minimize plumbing)

Or maybe just keep the original design and run pumps on timer instead of bell siphon?

Large beds with siphons work just fine. The same principals work in both, it's controlled by the amount of water going in, and out, it doesn't matter if it's a massive bed, or a tiny one.

But as for the slope in the fish tank, it doesn't do as much to drain the solids, it's more the fish movement that moves all the solids to the standpipe. A slope doesn't hurt, but it'll be far more effective to just have the SLO in the middle.

It's not a great idea for two pumps, you're better off keeping one in the shed and swapping it around if something happens. If you buy a decent pump in the first place, it'll last considerable time, and there are plenty of monitoring options to keep everything working if you are worried. Two pumps also run the cost up considerably.

Just one thing to not with the larger beds, make sure your sump is huge if you want flood and drain (I wouldn't go constant flood with a bed that size, you'll end up with channeling, but others might disagree on that). For the sump size, you'll have 3600L of media (assuming you're going 30cm deep with the media), so you'll want 1000L for the amount it'll flood and drain, and on a hot and windy day, with lots of stuff growing, you could use up 400L. Make it big enough to give yourself a week and a bit between needing to top up (trust me that topping up every day sucks).