This paper develops an analysis of two opaque interactions in Campidanian Sardinian that involve metaphony and two other processes, vowel merger in the suffixal domain and word-final vowel epenthesis. The analysis is developed within the formalism of Turbidity Theory, a model assuming containment, combined with privative features, maximal economy in the representation of segments and relativized scope. The basic idea is that metaphony is computed synchronically as a non-local licensing condition of a feature {high} only if it is underlyingly present. We discuss, on the one hand, cases of non-application of metaphony induced by a subset of high vowel inflectional suffixes. We show that underapplication of metaphony in Campidanian Sardinian is due to insertion of a feature {high} in this set of non-low suffixes lacking {high} underlyingly, which does not need to be licensed as it is not lexical. On the other hand, metaphony also underapplies in the presence of epenthesized high vowels, because their feature {high} is again inserted since these vowels have no correspondent in the input. This paper presents an account that allows the implementation of the interacting processes such as metaphony, vowel merger and word-final vowel epenthesis into one parallel OT computation. With the help of work on inventory structure, the opaquely interacting processes can be modeled without relying on rule ordering.