Ohh I didnt miss it...I just didn't believe it. So I researched it in freshwater a little more.
http://www.planetinverts.com/killing_planaria_and_hydra.html
and more on it
http://www.aquaticplantcentral.com/forumapc/showthread.php?t=52784
and then there is this stuff
http://www.aq-products.com/APpro/clouttablets.htm
and this one list some fish and snails that will eat them
http://www.aquarticles.com/articles/management/Ali_Planaria_Worms.html
now everything I have looked at does point at to much feading and not enough cleaning...so that is the base of the problem....how you take care of them is up to you...but there seems to be more than just ONE option.
Ohh and I still think copper sulfate would work
Im chill baby im chill...I would get into debates at the lfs I worked at with coworkers when we were slow. One guy tried to tell me the city we were in didn't put enough chlorine in the tap water to kill fish.. That was an easy test....with de-chloranator on hand of corse.