This question relates to finding a commercial laboratory which has
experience in determining the particle size distribution of
suspended particles which naturally occur in seawater.  We wish to
submit our own sample of seawater to find out the distribution of
particle sizes to help us assess what type of filtration we may need
to use to clean this type of water even further.  By understanding the
size of the particles, we can better specify the type of filter we
need to perform a very specialized type of filtration.  The sample
that we wish to submit is very clear, and likely contains only very
small particles.  Industrial labs without experience with seawater are
of lesser interest to us, as they seem to deal with samples with a
larger
quantity of particles. A good answer will contain the contact
information for one or more commercial laboratories in the United
States who are willing to
do this sort of analysis on a fee for service basis.