Um, we have Hawaiian and it is ferrous. We ended up taking the magnet cleaner out of our tank because anytime you got close to the sand it would suck it up and we ended up with a few nice little scratches. I don't know if maybe it depends on the brand you buy or what but ours is definitely magnetic. Don't get me wrong, it's beautiful and I would it again tomorrow, just not with a magnet on the glass. Now we just use an old credit card to scrape the glass when we do our water changes.