Not all of the spheres will be the same size or shape, by using a square and the 'square packing' method surly that biased and unscientific.
By square pack when forming a single layer in a recess, only conforming media would fit to achieve the neat row formation.
Your basing the square packing idea on that all the media is already of the same diameter and shape.
Is not taking a percentage of fails in an area where alignment of particles is not forced fair, by expecting that a predetermined amount will fit neatly in the sample area you are not testing accurately but predetermining that all media in the sample are already conforming to the required size and shape.
I thought that the media was to be poured into the recess and excess removed, how can they be poor into rows again this is biased and not accurate or fair in my opinion.
