aiptasia eradication advice

[russp]

my reef has been established about a year now & for about 10 months i have been watching a hitchhiker anemone grow larger & larger , I suspected it was an aiptasia but because it was the only 1 in the tank i was not worried. recently i have noticed 1then 2 then 6 baby nems appear around it so tonight i decided it was time to get rid of them. because they are on an easily removed rock i placed the rock in a pail of tank water & layed into them with the aiptasia x , when i dosed the big 1 it let out a big gush . my question is is did this fella just seed a million baby's onto this rock ? am I safe to put the rock back in the tank or what. any advice would be appreciated.