OK...from other threads I can assume they are calcium flakes. But strange to me since the pool is balanced. Normally my TA sits at around 70 and I never see this even as the pH drifts up to a 7.9. But I added some Baking Soda a few days ago, more than usual so I ended up at 90 TA. Thinking I will keep the pH down around 7.5 until TA come down a bit.