Help - Chalky White Clump

[twiglet1003]

Hi everyone,
I'm new to this site - and to posting on forums in general although I have had my Hermann Tortoise, Raf, for nearly 6 years.
I'm just looking for some advice - Tonight when getting home from work I went to check on my boy, who seemed absolutely fine in himself. Charging around, rapaidly munching on the weeds that I had brought him and just generally looking for attention.
However when reaching in to his table to change his water I noticed that there was a hard (chalky) white lump about the size of the end of my thumb laying next to his water bowl.
I picked it out and it was crumbly, but nothing like I have ever seen come from him before and tbh it looks like it would have been extremely uncomfortable for him to pass. Normally the white stuff comes out with his pee and is watery.
We pulled him straight out and got him in the bath (he has on average 3-4 baths a week in lukewarm water for around 15 mins but he absolutely hates being in there, even to the point of flipping himself over trying so hard to get out which is scary - I watch him like a hawk) as I was concerned its dehydration!

Could any of you please offer me some advice? Im really worried and feeling like an awful mum, with an instant feeling of I dont know what Im doing! I dont want him to be suffering in anyway!!

Thanks in advance

Laura

Ps. I took some photos of it but I don't know how to attach them. It was about the size of the end of my thumb and round.