Hi! I'm new to this forum, so patience please!

I have a 16 yr old male RES (Turtle-Boy) and recently took over the care of a 2 or 3 yr old RES (Little Buddy) that I believe to be a female. I have them in separate tanks. Little Buddy was doing great for a few weeks - eating like crazy 2x a day, swimming great etc. About a week ago she didn't eat her evening meal and her water went pretty foul overnight from the uneaten food. Cleaned the tank in the morning - still no interest in food. Up until this she was pooping nice dark normal poops regularly and I was sucking them out the tank with a turkey baster. Since this episode, she's pooping these really strange poops - milky white, odd shapes, they are somewhat hard and seem to have a milky coating over them. Some look like a tiny bean but most are just a glob of a thick mass consistency. I thought they might be urates, but have yet to been able to find any photos on line to confirm that. I don't see any evidence of worms in the poops. So, I'm wondering if she's just mature enough and these might be malformed eggs or something. Does anyone have any experiences like this? Thanks!