Using Stoke's Law for Determination of Terminal Velocity

Dear sirs,

Now I am working on the project where we are installing a line to transport a water which can contain significant quantity of sand. Main purpose is to size this line diameter small enough to have the actual fluid velocity less that terminal velocity to avoid the sedimentation of sand. Particle size is < 250 micron. Reynolds number in the piping is 90805 ....

I want to use a Stoke's Law for the determination of the terminal velocity, am I right?

Thanks in advance.