: Can the old wax be reused without adding any more?
Old wax should never be reused. You need new wax each and every time you set a toilet.
: : A couple of things bother me. The plumber said the wax ring was good, but he added a thin ring to it anyway? This is likely why the toilet has become a rocking chair and the wax has spread past the edge of the toilet base although there quite a space between the wax ring and the edge of the base of the toilet. The toilet must set solidly on the floor. If the floor is slightly off of level, the toilet can be shimmed. You say he tightened the tank bolts, but you found one loose after he left? Either he tighten the bolts or he didn't, and you must be very careful when you tighten tank bolts. Too much and/or uneven tightening will crack the tank. In fact, I wonder if perhaps that is the problem with the leak. A hairline crack is very difficult to see, so don't rule out that possibility. As to what to do, the answer is simple. You hired the plumber to do a job that wasn't done. He has to come back and do it right. On a positive note, the $101 charge seems very reasonable.