A method for correcting nucleotide incorporation signals for fluid potential effects or disturbances arising in nucleic acid sequencing-by-synthesis includes: disposing a plurality of template polynucleotide strands in a plurality of defined spaces disposed on a sensor array, the template polynucleotide strands having a sequencing primer and a polymerase bound therewith; exposing the template polynucleotide strands to a series of flows of nucleotide species flowed through a fluid manifold, the fluid manifold comprising passages for flowing nucleotide species and a branch passage for flowing a solution, the branch passage comprising a reference electrode and a sensing electrode; obtaining a plurality of nucleotide incorporation signals corresponding to the plurality of defined spaces, the nucleotide incorporation signals having a signal intensity related to a number of nucleotide incorporations; and correcting at least some of the plurality of nucleotide incorporation signals for fluid potential effects or disturbances.