Bernoulli Standpipe
- 1" slip to 3/4" male pipe thread (MPT) adapter - $0.77
- 3/4 in. Sch. 40 PVC Pressure Slip x FPT Adapter - $0.44
- 5.5 inch length of 3/4 in. PVC Schedule 40 Pipe - $1.97 for 10 feet, $1.15 for 2 feet
- 3/4 in. Male Terminal Adapter - $0.46
- [A 1 inch diameter hole drilled through the bottom of your grow bed]
- #18 O-ring - $2.27 [for Box of 10]
- 3/4 in. Female Conduit Adapter - $0.50
- 5 inch length of 3/4 in. PVC Schedule 40 Pipe (already bought)
- 3/4 in. PVC Sch. 40 45-Degree S x S Elbow - $0.62
- 5 inch length of 3/4 in. PVC Schedule 40 Pipe (already bought)
- 10 inch length of 2 in. PVC Sch. 40 Pipe - $3.69 for 2 feet
- 2 in. PVC Cap - $0.98
- 11 inch length of 3 in. PVC Sch. 40 Pipe - $5.95 for 2 feet
All told, the parts add up to about $20 if you're just building a single Bell Siphon. If you build two of them, they come in at $14 apiece. Or if you get a bunch of friends together to build 10 of these, the price comes down to $9 apiece (because you'll buy the 10 foot long lengths of 2-inch and 3-inch pipe - economies of scale).
Now that you've got the parts, here's how to put it together:
Small system I put together for a Feb 2012 science fair
Installing the Bulkhead fitting (the grey conduit bits and O-ring)
Assembling the Standpipe, Bell, and Media Guard
Different Discharge Options (I like the 45 degree or Coanda Discharge)
thanks for the great demo and plans. The one I have now I got off Ebay and one off craigslist and neither one seems to work correct even after me playing around with them. I will make my own from your plans and see what happens. Thanks, Joe
ReplyDeleteA lot of the older designs use epoxy for tubing to help break the siphon, and the discharges use 90 degree elbows, which are finicky. The simple design I show above, along with the 45 degree elbow on the discharge, work really well. I suppose if I were a nice person, I would go to the bother of making these available on eBay. But they're so simple to make, I'd rather let other people do them for themselves.
DeleteBy the way, I ended up getting tapped to write The Complete Idiot's Guide to Aquaponic Gardening for Penguin Book Group. The book is now available for purchase at Amazon.com. It includes lots of DIY plans (including for this bell siphon) as well as everything I wished I could have found in a book back when I was starting out (which wasn't very long ago...). So far the reviews are good!
My goldfish are slowly dying evey few days. I have a aquarium test kit and each week the tests all show within normal safe levels.
ReplyDeleteI have my grow tray above the fish tank and have various veggies in the Grow medium Hydrotron.
If I get some talapia will they be hardier and not have problems dying off?
The same thing happened to my mother - it's possible that your fish had an illness to start with, particularly if they were the inexpensive feeder fish.
ReplyDeleteI assume you let the chlorine evaporate from the water? You're feeding them enough, not too much? Is the tank inside or outside? If outside, the summer heat might be too high. This will depend on where you've got the tank, etc. I use an inexpensive digital thermometer - you can buy them in pet stores (often used with reptiles).
You might want to visit the Aquaponic Gardening Community and see what folks there say. Good luck!
Tilapia can be hardy if you can control their temperature. I had a batch of tilapia fingerlings that all died off - probably because my basement wasn't warm enough during the winter when I first tried to set up a big system. I've found many places regulate tilapia significantly. FWIW, I use bluegill in the system which is now outdoors. They're pretty hardy.
DeleteMeg
DeleteI am going to use a bell siphon in my system. My gbed on the bottom is 1 inch thick. Will this not be able to be put in? Does it need to be small athe bottom for the adapters?
Hi Nicko,
DeleteInstead of using the conduit connectors, you can buy a regular 3/4 inch bulkhead fitting. I've purchased these from Amazon, and they should be long enough to work with a thick bottom. Below is a link for a pack of 5 for less than $20.
Bulkhead Fittings, Builder's Pack of 5
the bottom hole is an inch so would I need an inch bulkhead fitting or still 3/4 inch bulkhead fitting?
ReplyDeleteHi Nicko,
DeleteYou'll need to drill the hole so it is big enough for your bulkhead fitting. If you are using the 3/4 inch conduit fittings you will need to drill a 1 inch hole (sinceit's the inside diameter of the pipe that is 3/4 inch, and the connector is roughly 0.125 inches thick from the inside to the outer diameter of the threads, or 0.25 inches thicker than the ID of the pipe.
If you use the 3/4 inch bulkhead fittings from Amazon, the hole needs to be 1-1/2 inches in diameter, according to the website.
I wanted to thank you for taking the time to post all of this. It was the kick in the pants I needed to get my siphons built... along with the rest of the system :) Its been three days, and they are working like clockwork! :)
ReplyDeleteGreat to hear your siphons are working like clockwork! By the way, I was asked to write "The Complete Idiot's Guide to Aquaponic Gardening" for Penguin Book Group available 2 April 2013. It's got many DIY plans and everything I wished I could have had in one book when I started my aquaponics adventure. Information on plants, fish, pest control, nutrients, etc.
DeleteThough I wouldn't have refused royalties, I was offered a contract to write this book as "work for hire." That means I don't make any more money just because you buy the book or tell your friends about it. But if you find it useful or think it's worth recommending to friends, I would be honored.
Well, if its anything like the stuff I see on this site, its going to be WELL worth it! :)
ReplyDeleteIs there any cheaper 3/4 inch bulkhead fittings? Thanks Meg! CONGRATULATIONS ON THE BOOK ALSO!!! I will recommend to friends as well as buy a copy!
ReplyDeleteWhere did you find the tanks? They look very heavy unlike to fish pond ones that I have been looking at. Thanks, very informative.
ReplyDeleteThe tanks I use in these videos are stock tanks, used for watering and feeding livestock (cows, sheep, horses, etc.) You can find them at agricultural supply stores like Southern States, Tractor Supply Co. You can sometimes find the 300 gallon tank online at the Ace Hardware website.
DeleteAnother option is building tanks or grow beds using a liner (duraskrim or EPDM pond liner) inside a sturdy box framed by lumber. Most of the built tanks I've seen use plywood, but I've also seen people simply use thick extruded polystyrene foam for the walls of grow beds inside the lumber frame, which insulates the system from extremes of heat and cold.
Whatever you do, check it out filled with water and (for grow beds) rocks before adding fish. One family made their own PVC tank only to have it burst when 75% full. They adapted by encasing the original tank in concrete.
Another option some folks use is old bathtubs. I've not done that, and don't know what adaptations one would need to make to the bell siphon and bulkhead for that purpose, but I also know there are shops that sell bathtub siphon kits.
My bell siphon has issues stopping to let the gbed fill back up. Why could this be? We built it specifically to your designs.
ReplyDeleteTHanks
If you bell siphon has a hard time breaking (i.e., your grow bed stays dry), your flow rate is likely too high. Turn the flow rate down, and the siphon should break.
DeleteIf your find the bell siphon isn't starting (i.e., your grow bed stays flooded), your flow rate is likely too low. Turn the flow rate up and the siphon should start.
It's counter-intuitive, but that's how it works. Good luck!
Thanks!! I turned up the flow rate by pouring some water in and it triggered fine...now all I have to do is buy a higher gph pump. Thank you!
ReplyDeleteOur bell siphon will start and stop but it stops when the water level is half way down. Why does that happen? It doesn't do a full siphon. It just suddenly stops at around the halfway point. Thank you!
ReplyDeleteDo you know where the holes are in your bell? The rocks in your system act a little bit like a sponge, so the water right at the bell will be a bit lower than the water in the rocks at the far end of your grow bed. When the siphon breaks, the water level in the entire bed will normalize, and the water level will be a bit higher than the highest hole or slice in your bell.
DeleteIf you've got a media guard, it's easy to simply pull out the bell. You can either make a new bell, or you could experiment by taping the higher slices/holes with something (I think I have electrical tape on one of my bells).
Good luck!
yeah we thought of that as well, but it isn't getting anywhere near the holes. The water level stops a good 3 inches above them. Our bell top is completely sealed, and it triggers by itself, what makes it stop prematurely
DeleteVery odd. It's possible that the top of your bell is too high above your siphon. Since air is more compressible than water, having a large volume above the top of the standpipe allows a lot of air to remain in the top of the bell, and that excess air in the bell can break the siphon even if you aren't getting air coming in from the bottom of the bell or the standpipe itself.
DeleteI've got a video showing a mini system with a glass jar as a bell, which lets you see what is happening inside a bell. You can see that even when the siphon forms, there is air remaining in the bell.
Good luck!
how do i set up my grow bed for my plants. and how do i make the grow bed so my plants roots have room to grow down. i will have a fish tank but i don't want the roots to be in with the fish
ReplyDeleteI am trying to up-size the bell siphon to release the water faster but am having difficulty.
ReplyDeleteI am using a 2" stand pipe with a 3x2 reducer on top.
The bell housing is 6 inches with a flat rubber cap.
The coanda pipe is two inches and situated under the water.
I'm getting plenty of water going through the pipe but the system will not start. Any suggestions?
A friend of mine had a similar problem. He ended up adding hose that when not in use curls up (like fire hose?). That helped form the plug required to start the siphon.
ReplyDeleteRob Torcellini came up with a bell siphon design to deal with very large grow beds. It involved creating a U-bend in the drain line that would remain filled with water, so the "water plug" was already in place. It also involves a bleed line in the top of the bell that siphons water from a cap next to the bell, allowing the siphon to break in a very large bed.