I take a lot of probiotics tho. I noticed the florastor seemed to help in a way the regular didn't but I usually take a probiotic with 30 - 40 billion probiotic cells in it.
Also it's been maybe around a month since stopping the Antibiotics . I'm still not sure about the black pieces tho I feel like they could indicate something, maybe with time it could clear up tho. I feel a diet could help too but it's hard to stay on one tho I do try to minimize Sugar and wheat when possible.