Ok, let me suggest a better way of dealing with the mysis shrimp.  First off, rinsing AFTER enriching with Vibrance or SpectraVital ( Marc Weiss products ) defeats the whole purpose.

Here is what I do:
 1) Break off a chunk of frozen mysis put in a cup and thaw.  I put mine in the microwave on very low setting for 18 seconds.  Do not do this for too long or you will destroy the nutrients.
 2) Put the chunk into a fine mesh strainer (available at your local housewares shop) and rinse THOROUGHLY with distilled water.
 3) Shake them dry and return to the mixing cup.  Drain off any remaining water either by pouring it out or using a paper towel to blot them dry.
 4) Now, add the enrichment.  Mush it around for 30 seconds to be sure it is embedded properly.  Do not damage the shrimp by mushing too hard!
 5) Feed to the horses.

You will notice that the shrimp are relatively dry when you enrich, which makes the Vibrance really stick, which will be evident by the lack or reduction of effluent in the water when you feed.