the way the dialsea works it runs your tank water thur a membrane. Then gets reading for salinity, CAl, Alk ,PH,temp, phoshates, copper you name it its checking it and then if you need to up your levels it will do it for ya. if you need salt the line that is ran from the barrel of salty water will add just enough to make it at the salinity that you requested.
it comes with numerous probes for checking the water.
nice piece of kit but to get the deluxe model its going to cost ya ......
I thought about get ting one when I come bac kfrom Afghanistan.