Possible tail rot/grey stuff in poop

[FeyaSG]

Good day,
I recently bought bearded dragon, male - Baltazar - from local petshop. He has been eating well, pooping normally daily, but one think has been bugging me. I keep thinking if this black thing on his tail is tail rot or not, his tail has been black-ish even before i purchased him. Humidity in his enclosure is on normal level. I do not know his age, the store clerk has not been the best one. And today, i found his grey stuff in his poop. Is that ok or not? He has been storing this poop for two days.
Thank you.
PS: These photos have also been taken after has had his bath.

 

[FeyaSG]

Looks like shed - keep an eye on it if it gets blacker or looks like it's getting dryer and bristle then it's time to see a vet - the poop looks ok what have you been feeding him? Extra water is good means he's hydrated

He has had the black-ish tail for month or two now. He is getting crickets and few mealworms with calcium daily, and vitamins every 2 weeks, alongside with mustard greens, collard greens and berries once a week.

 

[FeyaSG]

Vitamins should be 2x per week - I will post info about tail rot later and then we can see if that is what it is- has he had any injury to the end of tail?

Not any injury that I know of, but ive noticed a something at the end of his tail, like a row of his scales missing, but it hasnt had any big impact on him at all