We have found that silicone made tubes work better than PVC ones, They are more flexible and can be glued with Silicone, which makes them more air tight.

We have used two different tube sizes:

1. 4mm Outer Diameter ⇒ 4mm Inner Diameter - These were the most wildly used tubes. They would connect to the actuators, to valves and to the thinner edges of splitters.
2. 6mm Outer Diameter ⇒ 4mm Inner Diameter - These would connect to the pumps and the thicker edge of splitters.