Probably, you'll need to post pictures. Use Webshots, Flickr, Google Drive, etc. Or, email them to poolforum@gmail.com.
You can try describing their color and appearance but that may not help -- people tend to describe the same stains in different ways.
But . . . it's grayish mottling stains, AND the plaster is new, then it's a pool plaster problem. Unfortunately, the Plasterer's Council has pretty much taken the position that discoloration like that is NEVER the plaster's fault. So, lots of luck trying to get it fixed.
To the best of my knowledge, it pretty much takes a re-plaster, anyhow.
Here are some links to different discussions:
http://www.poolforum.com/pf2/showthread.php?12189
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