I took license with your question, assuming you meant conductivity instead of connectivity. My apologies if my assumption is in error. As salt in solution increases, so will conductivity (a measure of ability to conduct electrical current) readings also increase. I am not certain if this change is fully linear throughout the concentration range, so you might need to check that or see if literature has the relationship. As with any laboratory work with instruments, regular running of standard concentrations is important to insure quality, and should also suggest if your instrument or settings are correct. Conductivity is the inverse of resistivity, if you find some use of that term in some studies. Salinity is also directly related, but different units.