Comment on "Combination of cupric ion with hydroxylamine and hydrogen peroxide for the control of bacterial biofilms on RO membranes by Hye-Jin Lee, Hyung-Eun Kim, Changha Lee [Water Research 110, 2017, 83-90]".

The methodology employed by Lee et al. to terminate their bactericidal assays was found to be flawed via our demonstrations. Briefly, EDTA or sulfite combining with cupric ion did not fully terminate, and instead even boosted the P. aeruginosa death. We therefore suggested them to seek for other means of reaction termination, such as the combination of buffering agent PBS and Cu(II)-complexing agent EDTA.