There should be really no need for them in your tank. In a tank that has an established bacterial colony which breaks ammonia down into nitrites and the nitrite into nitrate, there should be no ammonia or nitrite detectable.
In fry tanks there should be some kind of filter, usually a sponge, and that should have all the essential bacteria, (where the fry tank is kept cycled with fish or pure ammonia, or the sponge is kept in another tank's filter while the fry tank is not in use).
In any case, using the ammo chips in an uncycled tank will take valuable food away from the bacteria, making the cycling process even longer. In cycled tank, the ammo chips are useless because the ammonia is being all used up by the bacteria.
If you have fish in a tank with ammonia or nitrite readings, it's better to do a 30% water change every day than to add chemicals or similiar to the tank.