Powder soap was at one time, the only dishwasher soap available for automatic dishwashers. Liquid soap came later and while it is not quite as good at cleaning as powder soap, it works better in low water temps than powder soap does.

The latest innovation is powder soap with scrubbers pounded into hockey like pucks.

They work well and I personally use them. But.....I have ran into a snag lately with these puck/disc like dishwasher soaps. While most North American dishwashers can break up these soap pucks during a wash cycle, one brand has had trouble breaking up these puck/disc's.

The soap door opens and the soap is open to the washing environment of the d/w...Most dishwashers today use both spray arms ( not on all models ) during the wash cycle, or have a hard spraying action. Frigidaire ( and many European styles as well ) uses a "softer" washing action that rotates the upper spray arm a while then rotates the lower spray arm for a while back and forth, never using both at the same time. This gives a much quieter operation noise level and this type of a washing cycle is gentle on the dishes, it has trouble dissolving these puck/disc like soap tablets. Frigidaire does not recommend using these soap in there full size dishwashers with this type of a washing system. Figidaire owns the names, Frigidaire, White Westinghouse, Tappan and Kelvinator.

I thought you might want to know.