The best dishwasher detergent and I what I use is the Cascade Complete Powder Dishwasher detergent.
The Cascade Complete Dishwasher detergent gets my dishes clean and leaves no residue on the dishes when used.
I've also used Seventh Generation Ultra Power Plus Dishwasher Packs in my dishwasher and those work great as well.
But my go to dishwasher detergent brand is the Cascade Complete Powder Dishwasher Detergent.
I have also in a pinch used some regular dish washing liquid in my dishwasher and it worked out okay when I was out of dishwasher detergent and could not afford anymore.
But the dishwasher detergent is what should be used in a dishwasher as it creates less suds and leaves less residue on your dishes.