  We have succeeded in growing very high purity (99.995%) YBa_2Cu_3O_{7-delta}
crystals in BaZrO_3 crucibles and have measured Delta-lambda(T) and R_s(T) at 1
GHz in crystals with various oxygen treatments. For an oxygen vacancy level of
delta=0.007, Delta-lambda and R_s essentially reproduce our previous results
and show no sign of the existence of the two order parameter components as
recently reported by Srikanth et al. on BaZrO_3-grown crystals. For other
oxygen concentrations, we have in some cases observed deviations from the
linear low T dependence of Delta-lambda, but never any sign of a second
transition.
