I have had this product for almost 4 years and am still trying to find a way to not have soap scum left on my dark clothes.  Today I added 4 pitchers full of water because the water level is so low even for small washes.  Then I added a small amount of soap in the last pitcher of water.  After it spun and stopped, I took out my clothes and found that the 2 navy items had soap scum on them.