A method of forming a plurality of lipid bilayers over an array of cells in a nanopore based sequencing chip is disclosed. Each of the cells comprises a well. A salt buffer solution is flowed over the array of cells in the nanopore based sequencing chip to substantially fill the wells in the cells with the salt buffer solution. A lipid and solvent mixture is flowed over the array of cells to deposit the lipid and solvent mixture over at least some of the wells in the cells. A first portion of the cells, each having a lipid bilayer over its well, is detected. A second portion of the cells, each having a lipid membrane but not a lipid bilayer over its well, is detected. An electrical lipid-thinning stimulus is selectively applied to the second portion of the cells but not to the first portion of the cells.