SAN ANTONIO — Omaha, Neb.-based Metonic Real Estate Services has purchased the 230-unit Sierra Ridge, a multifamily property located in northwest San Antonio, on behalf of investors. The apartment complex is currently 94 percent occupied. Omaha-based Seldin Co. assumed management responsibilities upon closing. Seldin is planning extensive upgrades to the interior of Sierra Ridge, which was built in 1972. Gables Residential was the previous property manager.