Yes, the air pump is not actually injecting air into the water. An ordinary air-pump for aquarium use of around 2.5L/min is more than enough for a 50mm dia. pipe. Differences between solenoid valve? Just consider the cost and use of metals of solenoid valve, the hazards when electricity is being...
Any chance you could post a link to where we can find a pneumatic valve? Looks like a great idea.
It is a new product which will be first shown in the coming AQUARAMA 2005 in Singapore on 26th May,05. A description leaflet on the system is attached.
