Well I got that the majority of people run co2 at 24/7 including you Rex.
http://http://www.plantedtank.net/fo...off-night.html
I read the ph rises harmful theory on The Krib and pretty much all over the internet. I personally think that either way will work fine as long as you look for any problems. What's wrong with the needle valve? Should I go with the previous setup and look for a better needle valve? I think the Azoo needle valve is just fine.