I thought I had a good handle on spa water chemistry until I read this article about MPS from the Medina County Health Department:
In particular, this quote has me very confused, "This product is used to eliminate organic contamination. It will NOT remove combined chlorine (CC). Therefore, it is not equivalent to 'Superchlroination'... MPS is mainly used to oxidize organic matter which increases sanitizer efficiency by 'freeing up' more product to be used for disinfection."
I thought "oxidizing organic matter" resulting in "freeing up more product" IS the process of removing combined chlorine from the water. Every other description of MPS I've read seems to indicate that it replaces the use of chlorine as an oxidizer, hence the term "non-chlorine shock", which indicates that its purpose is to oxidize chloramines resulting in reduced combined chlorine. Am I missing something or is this article way off the mark when it claims that MPS "will NOT remove combined chlorine?"