My stools been quite black recently as well (i'm chelating as well). It's also got small white lumps in it. I'm glad they're leaving my anyway. I've always had problems with my bowls (i was diagnoised with IBS).

Last summer I passed some parasites after eating a ridiculous amount of pumpkin seeds. I did a parasite clense aftwards (a la curezone) and nothing came out. I may do them (liver and parasite clense) after I'm feeling the positive benefits of having lower mercury levels as I'm thinking maybe my mercury levels made clensing difficult before.