Choosing a dishwasher detergent used to be simple. But after manufacturers removed polluting phosphates two years ago, some detergents couldn't get the job done.
Consumer Reports tested more than a dozen products to find out which ones get the job done at the best price.
Carol Kuen couldn't figure out why her dishwasher wasn't cleaning her dishes very well, and why they were turning filmy.
"I tried loading the dishwasher differently. I tried different detergent. I tried different rinse aids," she said.
When Consumer Reports evaluated detergents last year, testers found some left a white film on glassware.
Consumers complained, too, so some manufacturers reformulated their phosphate-free detergents.
"We developed a tough hard-water test to evaluate these detergents. In hard water, glassware is likelier to develop a film," said Bob Markovich of Consumer Reports. And aluminum can discolor.
Testers loaded a dishwasher with clear plates and with small aluminum sheets that stand in for pots and trays. They added detergent and repeated the test 20 times.
To see how well the detergents clean away food, Consumer Reports performed another tough test. A messy mix of 17 ingredients, including peanut butter and eggs, was applied to plates, and then baked on.
"some of the worst-performing detergents left food on the plates," Markovich said.
The lowest-rated detergent - Green Mission Organic Dishwasher Gel from Whole Foods.
But Cascade Complete with Dawn Actionpacs was a clear standout. Great Value Powder Pacs from Walmart was close behind and costs far less. Both do a very good job cleaning dishes, and they don't leave a filmy buildup.
In addition to choosing a good detergent, Consumer Reports says there are a number of things you can do to get your dishes cleaner. Use a rinse agent. Load properly -- that means the dirty side of the dishes should face toward the water jets. And separate your flatware.