I asked them there for a solenoid for CO2 and they said no. They said they had for air or water I think. Not sure if that works.
Me neither. Anybody else knows?
It seems that we need a pneumatic solenoid? Parker produce solenoids as well as needle/metering valves. You can ask or call the guys here http://www.petrotech.ae/store.html#
since they seem to be a Parker dealer. Maybe they will have both? If not I am afraid you'll need to strip search Shuwaikh. Seems very ironic a petroleum rich country is quite poor in valves/regulators. If you searched harder I am somewhat certain you'll find what you need but you will spend A LOT of time since the people working have absolutely no clue except for prices. You will need to search the inventory yourself.
In a couple of days I'll be back on the search since my Co2 tank is up to date. I'll go looking in the Friday market tomorrow (yes on a Wednesday). If I found anything I'll notify you. If you need help with anything (aquarium/hydroponics/aquaponics etc) just pm me.