This is a tough one.
First, let me say that using the dishwasher uses less water than washing by hand. Many people have tested this, and even if you are scrupulous about your water usage you are using more water than if you used an old dishwasher and pre-rinsed, people with new dishwashers have no excuse not to use them.
That being said – what kind of detergent should you use in your dishwasher? If you have soft water you can use almost any kind you please. Just don’t use one with phosphates or bleach in it. In other words, don’t use most of the ones you see advertised on TV and displayed in the grocery store. Use an environmentally friendly one.
If you have hard water your choices go down substantially. After testing a few, but not all, of the ‘eco’ dish detergents I have settled on the Ecover Ecological Automatic Dishwasher Tablets coupled with the Ecover Rinse Aid.
These seem to work just as good as the Cascade Complete powder with bleach and Jet Dry. I still get foggy glasses sometimes and the occasional dirty dish, but I did with Cascade too. I definitely notice when the rinse aid is running out!
My mom adds vinegar to her rinse water and this helps her. I can never seem to remember to do that though. Besides, I often run the dishwasher in the middle of the night.
Another prduct that is intriguing – the Magnoball Lime Descaler. I haven’t tried it, but apparently it softens the water in your dishwasher and washing machine which allows the detergent to work better. Who wants to try it out for us and report back?