Originally Posted by Ron Olson
Try industrial valves as they're made for high pressure. It may take one strong servo to move it though. Look for one that only takes 1/4 turn to open fully.
If frosting the tank ever becomes a problem then possibly water-warming it by using the rudder pickup would be an option. I'm just thinking out loud here.
that's a good idea to warm the tank water is good idea! i've never seen a small enough industrial valve but i'll keep looking. most of those are so hard to turn though, i've used sum that i had to struggle to turn and it was new! i've tried maching an air regulator but air molecules are so small! my valves were leaking with only a .005" tolerance! here's the valve that i think i'll put on the tank: http://www.ebay.com/itm/Aquarium-CO2...item3f081c59b6
i know it doesn't go to low in pressure (i though the smaller numbers were PSI
) but i know that i had found an even lower pressure valve from those guys. after i found that link i now think that aquarium valves will be good because they're usually pretty easy to turn and don't leak.