That's why I use Oxypowder 3 evenings before, so I get rid of lot of the waste. Instead of Oxypowder I also have taken 2tsp ES for the 3 evenings before.
By the time I do the flush the ES at night creates buttpee and the same in the morning, so you can just look at all the stuff that is floating.
Calcified stones sink, the only way you can see that is if you use a colander.
Even floating foam is good it seems they small crystals and you don't want them in your liver.