Hello everyone. I am trying to create a composite structure, by packing several components of polymer and hydronium inside a box that contains graphene. For that, I am using packing in amorphous cell module. In order to have a neutral system, I need to have the exact mole ratio of hydronium (20) and polymer (2). However, when I use this module, the output does not follow the exact mole ratio that I have determined for the system. For example, it packs 198 hydronium and 20 polymers. I was wondering if there is a way to get exactly the mole ratio that I am aiming at. 

If anyone can help with this, I would really appreciate it.

Thanks,

Mahsheed