Here's what I'm trying to achieve.
I have 8 soft tube pipe (usually found in fish tanks) coming out from a small manifold, to an aquarium air pump. The tubes then go into an aquarium.
I'm trying to control every individual tube, how can I achieve it?
What should I add to control the air flow for every tubes?
It's either totally blocking the air or allowing the air to flow.
Usually to swicth ON and OFF the supply of air, any pnumatic solenoid valves may be used which may be swicthed by 12 volts or 220V or any suppply they are built for. If you are trying to vary the air pressure from every tube, its a quite complicated job.
Using Silicone airline tubing should be easier to pinch open or shut, you might be able to achieve this with a cheap servo motor with an arm coming down on the pipe.
Late Edit - ensure you always have one airway open at all times or you will overheat the air pump and shorten its life - you will need a powerfull pump to get any useable effect from 8 outlets.