between the tub and the brass drain elbow there should be a rubber gasket. plumber's putty is used between the basket and the tub [for a seal] use a drain wrench to tighten the basket. use of anything might be able to loosen the basket [i.e. two screwdrivers, handles of channel lock pliers etc.] but to tighten the basket a wrench made for the purpose should be used. big box stores have them. the thread on the basket is a straight, not tapered thread.