Thanks for your help so far: I noticed that since species names are limited to 4 characters, I am running into problems. For instance, to save the mole fractions of HSO2, I need to specify MHOS2, which is rejected by the STORE(...,MHSO2,...) statement. Is there a workaround?

(Is it bad form to answer one's own message?) I suppose I could create a new symbol for this species, then use it in the chemical reaction files (and the trandat and thermdat files). Is this a PHOENICS problem or only a VR-Editor problem?

I am not sure if there is a workaround, but as a maintained user you can send the q1 and mechanism file to support@cham.co.uk and I will investigate further.

Thanks, Mike!