Continuous Flow?

[badflash]

Good video, but it doesn't need to be that complex.
This is all there is to a bell siphon:


I use a 1" standpipe in a 1" bulkhead fitting and a 2" pipe for the bell. Put a clean-out on the end and drill it for the aquarium tubing. I use silicon caulk to seal the hole and vaseline to seal the treads. You can't have any air leaks. The aquarium tubing extends down to the level you want it to stop draining. This needs to be above the notches at the bottom of the bell.


I use a 4" pipe with holes smaller than my gravel. This keeps the gravel from collapsing in on the standpipe when the bell is removed for cleaning. Be sure there are enough holes and that they are as big as possible. Cleaning out this strainer is a big job requiring you to remove most of the gravel. The strainer is not attached to anything. It is held in place by the growbed. You can pullout the standpipe and reach in to remove roots.


This is what it looks like when in service.


It Helps to have a slight upward slope about the diameter if the drain pipe. I've found this helps with the kick to get the siphon going.

If you are running multiple beds to a common drain be sure the return pipe is huge compared to the bell siphon pipe and that the drain pipe is vented with its own stand pipe that goes above the level of the beds. If you don't do this either some of the beds won't drain, or they will kick all at the same time and some will never get the right level of water in the beds.

Most of the time problems stem from flow too high or flow too low, or something being clogged up. Design your system so you can clean out every part. Growies get everywhere.

[urbanfarmer]

That's good advice. I have been worried about what would happen if my main system gets clogged. That's a lot of gravel to dig up... I feel I built it well enough to prevent any clogs, but you never know...

[rfeiller]

what i have done is get aluminum whire mesh with about a quarter inch grid, (it would have been better if i could have found 1/8" so i double up the 1/4" mesh to form smaller holes) that forms an inclousure about 2" all the way around the bell syphon. i flare the bottom of the mesh outward so the weight of the gravel keeps it in place. the mesh provides air pruning of the roots so they don't make it too the bell syphon.

this being my first bell syphon, it's been a real growth experience of digging out the syphon too many times. this is where i learned to hate hydroton.

[stucco]

Any chance of posting a photo of the wire mesh gravel guard?