7.09 Rich,  :shock: I assume thats a typo. 
  SS, that seems like a pretty large swing. My barely moves but under different methods. My friends 120, which is kalk dosed, seldom gets below 8.2 @ night and up to 8.4 @ day. Mine, {sump running,  

 }, is around 8.25 @ night and 8.4 @ day.