A method is provided that includes adding, using a polymerase coupled to a substrate, nucleotides in a solution to a first polynucleotide using at least a sequence of a second polynucleotide. The method includes separating, using labels respectively coupled to the nucleotides, quenchers from respective fluorophores. The method includes then detecting a sequence in which the polymerase adds the nucleotides to the first polynucleotide using at least fluorescence from the respective fluorophores.