I saw the people in the chemistry forum whining about it, then saying that they soak it for weeks in ro/di water to get it to leach out, then to do water changes on their holding water for the eggcrate. My thought? Give me a break. It's freakin plastic. I've put many sheets of eggcrate into my tank as frag plug holders, and they still have never grown algae on them (a surefire sign that they're zones of high phosphate concentration), and my tank hasn't had any phosphate problems (though I used to run GFO anyway). Now I run carbon dosing, so phosphate isn't an issue