I wear lots of dark clothes that have a bit of lycra/spandex.  I stick to cold water, turn them inside out, and use a liquid detergetn made for dark colours like Cheer or Woolite.  I used to use regular liquid detergent (my favourite is Tide Free), but when we got the front-load washer I found the dark clothes were getting white spots even though I was usuing the same detergent (and much less, like 1.4 cup).  When I switched to Cheer Dark the white spots disappeared, so I wonder if there's something special about that kind of detergen in combination with front-loaders.  I never had the white spot problems with the top-loader and the Tide Free coz I'd fill the tub up with water then detergent and get it mixed well before adding the clothes.  Can't do that with the front-load..