McNemar pair test, as each pair differs only because of the intervention and each outcome is dichotomous. (The commonly-used asymptotic McNemar test may fail for small numbers of examples, which is avoided by using the exact unconditional form. ) The relative number of the discordant outcomes reveals the directionality and magnitude of the effect. When N+-> N-+, water promotes crystal formation; when N-+ > N+-, water inhibits crystal formation. Table contains a summary of the results and statistical analysis; the electronic Supplementary Materials contains the complete machine-readable description and visualization of the experiment outcomes.