Problems with Purple up hardening in the bottle

[DanG]

I bought a bottle of purple up a couple of months ago, and have been using it every day or 2 to dose calcium and it's been a great product. Sometime after Friday when I dosed the tank last and Sunday when my brother came by to check on my tank, the last of the bottle (1 inch or so) has seperated into 2 parts, a super white liquid that clouds my tank for a good 45 minutes and a 1/4 inch of hard goo in the bottom of the bottle. I didn't leave the lid off, the temperature hasn't changed at all, I didn't leave it in the sun, it didn't freeze or have anything else added to it.
Has anyone else problems like that? I searched here and reef central and couldn't find any similar experiences.