Rich,
Solution B is a saturated sodium metaborate (Kodalk) solution. It really needs to be mixed with distilled water to get as much of the metaborate dissolved as possible. If you mixed with tap water, etc., you will likely end up with a lot of precipitate and a slightly weaker solution. This may only make a marginal difference in you results, but can result in negatives that are underdeveloped.
If you used distilled water to mix solution B, then the few undissolved crystals are a good indicator that you have the solution as saturated as possible (á la Rodinal). Shaking the solution puts a little of the undissolved chemical into suspension so it can be mixed into the working strength developer, where it quickly dissolves.
If you have large amounts of precipitate from mixing with other than distilled water, you can double the volume (using distilled this time) and then use twice as much solution B in order to get the correct amount of metaborate in your working solution (subtract the extra water from the water you add to mix a working solution for precise results).
Best,
Doremus