At the risk of losing immediate dishwasher sales, your current dishwasher works. You may have recently noticed streaking or spotting. The dishwasher is fine. Your detergent is not. There are new laws requiring dishwashers to use less phosphates.
Evidentally, phosphates are the cleaning agent, but they also do a pretty good job at creating assorted environmental issues like algae blooms. The best low phosphate detergent is this one.
Finish seems to clean the best, so try it....before scheduling a service call and paying a repairman $100 to say the same thing.
Speaking of dishwashers....Look at this one
The Bosch SHE43P is $399 in black and white and $599 in stainless after $200 in rebates until 11/17.