Hi Jbe!
The standard lid is open to atmosphere, so you wouldn’t be able to regulate the gas inside. However, the device uses standard test-tubes with threaded 22-400 closure, so you should be able to find some commercially available lid (or make your own) that fits those tubes and allows you to make a gas-tight seal on the tube.
Making a custom air-tight lid is something we are currently considering, but we would likely wait a while until we can have a big demand before ordering them in a large quantity… thoughts?
