dishwashers... I bought some dishwasher tablets today, for the first time in my life. I didn't read the instructions before I got home. It says stick the tablet in the dispenser thing in the door and to use Finish Salt and Finish Rinse Aid. Do I really need these last two things or are Finish trying to get my to needlessly purchase more of their products? I'm worried that the dishes will be toxic unless I use the salt and rinse aid.