The iodate pH oscillator, which oscillates between pH 6.5 and 4.0, is reproducible in a semibatch reactor. pH oscillations of similar period and amplitude were observed when poly(2-acrylamido-2-methyl-1-propanesulfonic acid) was substituted for sulfuric acid. Therefore, a polymer may be used as an alternative reagent, where the polymer actively participates in the reaction instead of serving as an inert reaction medium.