Definately not anything that needs scraping like coraline, specifically because of the concern of it breaking apart. As it was explained to me on a r2r thread, when broken down, the magic eraser is just another form of plastic and the "original" version holds none of the harmful chemicals that other versions hold. And we all use plastic in our tanks everyday. From powerheads to scrapers, acclimation boxes etc....
I will slice them into 6 even pieces and once a week wipe down my glass to get to the surface algae. I like that it "traps" alot of what it wipes instead of just releasing it into the water. Im a visual person and something about seeing the white pad turn because of the collected algae makes me feel glad to have gotten that out of the tank
I will stress however, that I'm very watchful. If my pad looks like it is getting brittle I remove it and I never use the same pad twice.
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