A second stab is taken at the reconstruction of the distribution of carbonate ion concentration in the deep tropical Pacific and Atlantic Oceans. It takes into account glacial to Holocene changes in size-normalized initial shell weights; it adopts a more rigorous relationship between measured core-top shell weights and pressure-normalized CO3= concentrations; and it employs an expanded glacial data set. While the conclusion that the effective glacial CO3= ion concentration decreased with water depth, when greater initial shell weights for glacial-age shells are adopted, the conclusion is that dissolution during glacial time exceeded that during the late Holocene. This conclusion is seemingly at odds with previous studies of deep Pacific sediments, all of which suggest that more extensive dissolution occurred during periods of interglaciation than during periods of glaciation.