The system can be calibrated at one or two points for pH and at one point for conductivity. Seawater salinity is expressed in either parts per thousand (ppt), Practical Salinity Units (PSU), or Specific Gravity (S.G.).
Testing and monitoring salinity in saltwater aquariums is an ongoing task. The HI981520 is an easy to use vertical mount unit that continuously monitors and displays conductivity and pH.