Reduced order particle based models have become popular recently for the study of ion channels. One of the key computational challenge for these methods is the fast and accurate calculation of electrostatic forces acting on the mobile ions. We have applied the electrostatic focusing method to address this issue. We have validated our method using bulk simulations and comparing the pair correlation functions with single grid setup. Full channel simulations were performed for ompF porin channel and important channel behavior like asymmetry of the channel and loss of selectivity at high bath concentrations were observed. We also observed the separation of pathways for anions and cations as they traverse the channel. Using focus grid method, we obtained an overall speedup of more than 50% for our channel simulations.