EOS5 but Helium in stead of Hydrogen

Hello,

I am trying to simulate a year long helium injection with varying rates using EOS5.

I'm wondering if I would need to change something in the source code for this to run correctly, and if so how and where should I make changes. Currently I calculate the amount of injected Helium by converting ml/s to kg/s by using the ideal gas law and the molar mass of hydrogen in stead of helium, would this be sufficient, or is there more to be changed (e.g. viscosity?). 

Best,
Matthijs