Thanks for the response. I was able to successfully add in CaO2 as a redox within the thermo dataset. And then was able to create a coherent expression in Rxn for CaO2 and H2O, however I am having issues with the React application. I have tried altering the input values and seem to keep coming up with errors, mostly stating that my "porosity of node 0 is too small". I am not sure how to proceed from here. Could you provide feedback on any issues with my parameters?