I realize this is an older post, but wanted to share some info that may help because I was a little nervous about using this in my clown fish breeding rig's sump. The stuff I bought was sold at Home Depot in the States as “dura-cool.” I shook it up in some water and didn't see anything except initial dust. I tried googling for a material safety data sheet for the product and found one:

https://www.dialmfg.com/technical%20...ool%20MSDS.pdf

The containing page for that link was he

https://www.dialmfg.com/technical%20...msds/msds.html

These MSD sheets have been very helpful in the past when I needed to check a glue, plumbing epoxy, etc. It appears the makeup is 40% polyester and 60% acrylic. I believe this is identical to many algae scrubbing pads and should be reef safe. I'm going for it after a good rinse. The rig doesn't have livestock in it so we'll try some cheap hermits in the sump and see how they fare.