I am getting lots of worms in my pool. These are not earthworms but little inch long white worms with brown stripes. I had my first outbreak about a year ago and it coincidently happened after I was told one of our grand children had an accident (#2) in the pool. This left me to believe the two incidences were related. I shocked the pool and held it at shock level for 7 days hoping to be rid of the worms. Just noticed today that the worms are back, could they be coming back because of something in my sand filter from my grand children's accident? I have not changed sand for 16 years. I plan on changing out the sand this weekend since it has not been done since the pool was built and maybe it will solve my worm problem.