Here is a helpful tip for porcelain throwers I learned at a Shakerag workshop with Mary Law in June. She, who works primarily with porcelain, puts a tablespoon of vinegar in her bucket of throwing water. This keeps it in suspension so it doesn't settle and leave hard sediment at the bottom that covers up tools and is difficult to remove. She finds it helps the consistency when she reclaims used clay, as well. I have tried it with half and half and like the results.
Hope it helps your throwing,