Coulter Count vs Silt Density Index

Dear All I am exploring about the seawater pretreatment requirements of injection water for water flooding operations.  I came across the Coulter Count quality parameter. A thought came to mind, while comparing the seawater pretreatment requirements of desalination plants for drinking purposes, people in this industry use SDI 15 as a governing quality parameter. Can I have your views on the differences of the coulter count and SDI value? Should we even try to compare those? Your thoughts please! Thank You Best Regards Anvar Mansuri