Backyard Aquaponics
A place to discuss aquaponics

I've only had trouble with siphons when I was walking the edge. As in, if you build a siphon that is just not in the size range of your flow rate, you will struggle with it and it may never work. If you are near the edge of the size or flow acceptable to a siphon, it will be more likely to need adjusting as flow rates change with time. If you manage to build a siphon spot on with the flow rate into the grow bed as well as the flow rate though your media, that is gonna be the siphon that runs without issue.

Another problem for siphons is fall or lack of it. If you try to design a system with siphons but don't allow enough fall for the siphon to clearly start and stop, it will likely have issues too.

Now perhaps a timer and stand pipe might be a little more fool proof for a beginner (as long as the timer doesn't malfunction or the drain holes get clogged) but I don't necessarily feel the desire to put fish in the hands of too many fools. Paying attention to proper feeding and making sure water quality stays good seem far more complex to me than a little plumbing tinkering.

I personally think the FLOUT is the most fool proof of draining devices.

You are very correct on the siphon there, normal stand pipe design will need to work at a very narrow margin of water flow. That is why after experimenting with siphon design for a long time I come out with a design that able to accept pump wattage from 12 ~ 30 watt without issue. the best to use 20 watt pump. If pump degrade you still have a huge margin to play with.

Can you explain to me what exactly the wattage of the pump has to do with the success or otherwise of a bell siphon??

Without any ball valve to adjust water inflow, the amount of water in is dependent on the pump wattage. Bigger wattage pump more flow in and vise versa, that all.

I have found that with a straight stand pipe design, it will siphon with certain pump capacity, smaller it will fail to siphon, bigger it will siphon but fail to cut off (if you do not have the air break tube)

Having a ball valve just restrict water flow, as if you are changing pump wattage. I try to use less component for my design, that is why I only use different pump wattage and not a big pump with ball valve to adjust.

With good bell siphon design, it can work with a broad range of pump sizes, in my experiment 12 watt to about 30 watt.., this will give you broad range of margin if a partial blockage occur or pump efficiency reduce with age. Using a say 20 watt pump with the valve I made will ensure trouble free operation over time.

You are very skeptical of the siphon I made.., I wonder why.., I am just trying to help Aquaponics enthusiast to have a chance to try out maybe a better siphon system. I am not making any profit of this design.. just helping others.