Will some one PLEASE tell me about the system that robo uses.
It is old trick. Take a glass container and a food plate. Put water in the container and a plate onto the mouth. When you twist that upsides down , water is locked inside.
Put the system on the tabel. Put 3 sticks between container and plate. It comes some water on plate and bubbles go into container.
When bees absorb sugar solution, liquid takes air bubbles and solution stays at same level.
Box enclose bees and system inside, and robbers cannot come to take liquid. Also warm stays inside.
In Finland professionals use same trick. They take a 10 liter plastic bucket, cover on and they make little holes into the cover. That system upside down, and liquid stays inside. When bees take liguid from holes, bucket takes air bubbles.
The cost of system is 2 euros. It needs a Langstroth box to enclose the system. I have used it, but I do not like it. Not handy.
Surely old fashion...