Each SWCG has its own requirements. Aylad is spot on right. You have to satisfy YOUR unit in order for it to produce adequate amounts of chlorine. 5 different pool stores (or tests) will give you 5 different salt levels. In the end, your Low Salt light or Salt Level Indicator on your unit must be satisfied for the unit to work correctly. And BTW cold water will affect your units ability to detect proper salt levels, so you can expect to see "Low Salt" warnings in colder weather, and consequentially, below about 60° F, your unit probably won't produce chlorine anyway.