I bought the float from a building supply shop in their plumbing department. You should be able to get something similar, if not the same. This is a South African developed float valve used in small applications where a normal float valve would not fit.
Hi Dirtychick.
When the container is filled with water it is too heavy for the birds to overturn. It is placed on a flat, level surface. I have never seen any of them sitting on the container. I think is is too slippery for them.
Hi Sunflower
It has been going for almost 2 months now with no hick-ups. I unplug the hose pipe every 2 weeks to wash the container out. The water stays remarkably clean.
I made this automated watering bucket for my flock and it works well. I fitted a float valve into this 25 Lt bucket that I cut open. I then connect the bucket to a hosepipe in my coop. It was easy and cheap to make. The photos speaks for itself.