This product is absolute twaddle, twit manufactured, dumb, inane, junk, joke, false, and garbage.
Had the material in my canister for three weeks and NOTHING has grown on them. I've got a smearable coat of nitrosomona bacteria on the basket they were in and stuffs not supposed to grow on that basket. I've got a gooey caking of nitrosomona on Seachem De-Nitrate that's only been in for two weeks and have started to see a reduction in nitrates on the tests.
I took out one of the NitraStrate beads and smeared it on a tissue and NOTHING came off, nothing is in it or on it. Its as clear as the day I put it in the canister.
However it is a very pretty bottom rock material and since nothing sticks to it it should be very very easy to clean! If you want to spend $6.00 per 250, which comes out to just about one cup of rock.
Verdict: don't use it, if it can't grow nitrosomona in three weeks, your fish is already dead.