if i remeber correctly doug had posted a link of a place where the sold puritabs or aquaclear tabs a long time back... And yes these tabs are tiny, very tiny. i don't know what the sizes are of nitro pills, so can't compair them. But the they are really small. Can't really compair them to iodine tabs, iodine tabs are banned here... Bit opposit of the US, so can't see a "significant indication". Proberbly determent by how much the companys wants to invest in testing and the will of the goverment. I do have to say that i find european law much strikter, wenn it comes down to the safety of it's citizens.