With the increase of digital movie streaming and rental boxes, traditional movie rental companies are facing some stiff competition. The Blockbuster on Brunswick Road in Grass Valley is set to close April 7, according to store managers. “Our prices are continually going down. Everything is up for sale,” said April Lund, Blockbuster manager. Three hundred Blockbusters have closed nationwide due to profitability assessment, said Barbara Ellis, Blockbuster director of marketing. “We are owned by Dish (Network), and Dish is continuing to examine the business and look at stores from a profitability standpoint,” Ellis said. “Profitability isn’t always dictated by how …