that regulator is junk. it's not very good at regulating, just on and off. worth about $15 or less. for $100 more you can get an oxygen cylinder and regulator that will be a permanent, reliable solution.
you don't really need to regulate it all that much. I use that assembly and a similar regulator although not sure you need all that if you're using an IC. I use a plate chiller so the assembly works great for me. You could just use an o2 stone and a regulator.