A method of analyzing a molecule is disclosed. A lipid bilayer is formed such that it divides a first reservoir characterized by a first reservoir osmolarity from a second reservoir characterized by a second reservoir osmolarity. An electrolyte solution is flowed to the first reservoir that tends to make a first change to a ratio of the first reservoir osmolarity to the second reservoir osmolarity. A voltage is applied across the lipid bilayer, wherein the lipid bilayer is inserted with a nanopore, and wherein a net transfer of ions between the first reservoir and the second reservoir tends to make a second change to the ratio of the first reservoir osmolarity to the second reservoir osmolarity, and wherein the first change to the ratio and the second change to the ratio tends to counter-balance each other.