A system and machine readable medium for nucleic acid sequencing includes disposing template polynucleotide strands in defined spaces disposed on a sensor array, at least some of the template polynucleotide strands having a sequencing primer and a polymerase operably bound therewith; exposing the template polynucleotide strands to a series of flows of nucleotide species flowed according to a predetermined ordering; and determining, for each of the series of flows of nucleotide species, how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands, wherein the predetermined ordering (a) is not a series of consecutive repetitions of a 4-flow permutation of four different nucleotide species, (b) is not specifically tailored to a particular combination of a particular template polynucleotide strand to be sequenced and a particular sequencing primer to be used, and (c) comprises a phase-protecting flow ordering.