I used to have the same problem with Cash - no matter what leave-in conditioner I used, his hair was tangly and it looked terrible.
Around the time that I was at my wits' end, I visited a breeder. Her dogs had such amazing coats. I asked what she uses (she grooms them herself) and she said she uses Pantene Smooth and Silky conditioner. I started using that along with a supplement (ShowDog from Nutureline) and now Cash has a lovely coat which doesn't tangle nearly as much.
I hope that helps. Btw, I know you aren't supposed to use human products on dogs, but Cash's skin allergies cleared up after I started using the conditioner!!
