Welcome to the site!
Sorry if this comes out harsh... Colon cleansing is a scam. Whatever came out of you was put there by the cleanse. They do that deliberately so it looks like the product is cleaning out nasty stuff you had lodged in there, making you think the serum worked so you go back for more.
Even if you're skeptical about
what I just stated, please check with your doctor before doing another cleanse. They have been proven to be dangerous if not done properly or under medical supervision.