Sounds like spring tails.

Spring tails originate outside your pool -- you have to deal with them there, before they enter the pool. Here's a fairly authoritative guide: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74136.html

And general info from Wikipedia:
http://en.wikipedia.org/wiki/Springtail

And, a thread from last year:
http://www.poolforum.com/pf2/showthread.php?14426

And, some pictures from Google Image Search (safe search ON, but still GROSS close ups of *bugs*)
https://www.google.com/search?q=spri...m=isch&safe=on