My father had this idea to use a chunk of thermocole for a basking dock for the turtles, so we tried it, and they seemed to like it a lot. But it seemed as if bits of it were breaking into the water, we could see small white floating particles, and I got worried that the turtles would eat them or something, so we changed the water immediately and threw out the thermocole

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I'd like to know if it's really harmful to them, and whether they would really eat it. They're very young, one inch or so in length.