Tundra Nenets (TN) has a complex system of alternations, many of which interact opaquely, and provides a good test case for the current theories of opacity. Categorical metrical vowel deletion in TN represents a case of self-counterfeeding opacity, and it also opaquely interacts with vowel deletion in final syllables. This paper shows that among OT approaches to opacity there are some that cannot handle metrical vowel deletion in TN in principle (Targeted Constraints, OT-CC) and some that can but are undesirable on theoretical grounds (Local Constraint Conjunction, in particular, self-conjunction), and that the full analysis of the data still requires combining two different theories (Stratal OT and Comparative Markedness).