Thanks for the infoI've used it for months without issue and I know others have for years when I was researching at the onset. Based off my understanding, the main danger with using this type of polyster batting would be if it is "siliconized." Fairfield sells other products which are clearly marketed as "siliconized polyster" while this one is not, so it should be safe.
Further, my diatom bloom from my uncured live rock has stopped while I have continued using the poly-fill, so I can also also anecdotally confirm that it hasn't been siliconized.
Long story short, I love this stuff and it ensures I swap out my filter floss every day or two since it is so dang easy.