purewater keyword in SPAM

[DDGmichigan]

Hello, For mixtures of two solvents ( A+B), A is 10% vol:vol conc and B is TIP3P water. purewater does not calculate the bulk free energy of the A co-solvent How can we use SPAM to use Mixed solvent interaction free energies, if the reference bulk value cannot be calculated. Any help will be so appreciated. Thanks