Backyard Aquaponics
A place to discuss aquaponics

Hey Guys.

I have rigged up a bell siphon that leads down to an aerator/silencer (both designed using affan's designs on his website) however when the grow bed fills and dumps it only dumps half of the water in the grow bed and goes back to a trickle. Basically it drops from 300mm water level to 150mm water level without any grow medium in it (as I am still working on it). Is having the plants 150mm above the water level up far enough to avoid root rot. It definitely dropped further without the aerator/silencer but it is something I'd like to keep attached for obvious reaons.

Your plants will be fine. I have a constant flood bed that never drains even with the pump off and the plants and worms are all fine.

Yep.... +1

You might find that you end up taking the bell off one day...

Your bell is breaking the siphon/getting air at the 150mm level.

Can you post some pics of your bell etc?

Cheers guys. Here ya go Arbe. I am thinking of putting a pinch point in the outlet pipe which is 25mm to reduce the flow rate. Ignore that PVC around the edge of the pond, that is actually a pond cover I am building to keep out the cats/my 19 month old

The bell setup looks better than any of mine so the bit going into the fish tank/sump must be doing something. Maybe it is not letting the drain run freely enough to finish and causing a backup pressure that is stopping it.

That would be my guess as well. If you can you may want to remove everything past that last 90 degree bend and see if that helps.

@LowCarbTNPer: It has already been mentioned that when the aerator/silencer is removed the water level drops further but for obvious reasons JackFrost wants to keep it.

I am wondering if you changed the 90 degree elbows to 45 degrees if that would make a difference?

Have you also tried it without the adaptor on the top of the standpipe?

More holes in the top of the silencer to release build up of pressure. As the water level rises in the sump or tank it also raises in the silencer increasing pressure not being released, thru what I can see ,two small holes. It does not take much to stop a syphon from working.
Cheers

Theres not enough holes in the surround for sure....

If this is being used, it will empty this really quickly when the siphon kicks there fore sucking air causing it to break.

I would suggest atleast 6mm Holes and i would have the bottom half of the pipe completly covered in them.

Thanks all. Will use your suggestions to tinker with the system and let you know how I get on.

I drilled those three holes in the silencer to 6mm and got the water level down to 130mm before the siphon broke but then I cut a couple of larger triangles out of the bottom of the bell dome and it now only drops to 180mm so I'll have to redo the bell dome.

Is the 'lid' glued on the dome? I have had siphons work but break early due to them getting some air from the lid.

Not yet as I don't want to go gluing until I am reasonably happy with it but that may explain the problem I was having as I am pretty sure I'd have loosened the lid when I was cutting the triangles bigger however I redid the bell done it with only smaller 4 triangle cuts and it is now breaking at 120mm so hopefully I'll get even more when I glue the lid.

And you sir, win the gold star! Works a dream now