Urates question (picture included)

[ziggythetort]

Hi folks...

I have a 3 year old hermanns tortoise. He hasn't passed urates for a few weeks and today he did... In his bath as usual, but it looked strange. (See attached pic)
I bath him every day, have a water dish in his enclosure and feed him fresh weeds and mix lettuce every day as well as adding nutrobol 3 times a week.
He's been a bit inactive the past few weeks, only really up about 2 hours a day but eats well.
Any suggestions as to why the urates are grey?

 

[taza]

Oh I have no idea, hopefully someone else will know.