GHL Conductivity extension Card

I am planning to buy a GHL Conductivity extension card for my Profilux 2 Plus, but I realized that there are 2 types.

GHL Conductivity measurement up to 100mS
GHL Conductivity measurement up to 2ms

If I want to measure Salinity, which one should I get, what is the difference?

Many thanks

Chris

I guess you want to measure the salinity in a marine water tank? Then you need the measurement range up to 100mS.