Hello. My name is Ivka and this is my first post on this forum. I have 200 liter tank and I used diy yeast co2 for about a year and now I want to upgrade. I have a regulator from co2 art and everything I need I am just a little confused how to connect regulator with co2 cylinder.so my question is befor I open main valve on cylinder do I have to have a needle valve and regulator open or closed? I am a bit worried cos I don't want to do something wrong. )