Hi total charge of my system (pr-dna) is (-10). which is better in genion command: 1) 10 Na or 2) 20 NA + 10 Cl -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20091115/64e75fc8/attachment.html>