hi sphinxlover,
this might help you
http://www.cichlid-forum.com/article...background.php
without any disrespect, from my opinion, i would not use styrofoam products to build any platforms whether its turtle, fish or any water creatures as it may contain nasty chemicals like formaldehyde for instance. its a lil' ingredient people use in medicine to treat sickness, but in a very small amount, too much of formaldehyde will cause health problems. to highlight it, this is something like humans can eat chocolate, but it is life-threatening for cats and dogs. there are a lot of people out there using styrofoams to build background for fish tanks too, but i wouldn't dare to use as it may affect the pH value in the water quality.
i found these infos from the internet, you might wanna check if this may be harmful to your turtle too. my two cents.
