Many large ontologies have been created which make use of OWL's expressiveness for specification. However, tools to ensure that instance data is in compliance with the schema are often not well integrated with triple-stores and cannot detect certain classes of schema-instance inconsistency due to the assumptions of the OWL axioms. This can lead to lower quality, inconsistent data. We have developed a simple ontology consistency and instance checking service, SimpleConsist[8]. We also define a number of ontology design best practice constraints on OWL or RDFS schemas. Our implementation allows the user to specify which constraints should be applied to schema and instance data.