If you were a fly on the wall, what would your staff be saying when you were not around? Are your employees happy and feel this is the best work environment they have ever been in? Or do you have back-stabbing employees, consistent fires and daily drama? These are two extremes and hopefully you spa's staff is relatively drama free and content. Many managers don't even realize or care about how their staff feels. This is the difference between an effective manager and a manager with ongoing staffing issues.
To be an effective manager you need to give your staff the opportunity to express their thoughts and feelings so you know when problems exist and how to put them to rest as quickly as possible. A weekly, mandatory meeting is necessary to keep the lines of communication open and to keep any egos in check. This is also a great way to develop trust and give your staff a time and a place when they know problems and issues will be addressed.
I hope you take the time to do an environmental evaluation of your spa and give your staff the chance to vent before it is too late. Remember it is less expensive to keep your existing staff happy and on board, them to find new ones!