Instant Ocean Hydrometer is accurate, reliable water test equipment is absolutely vital to creating and sustaining a healthy, successful marine environment. Easy to read and simple to operate, the Instant Ocean Hydrometer delivers precise full-range salinity and specific gravity readings - accurate to 0.001 - and does it each time, every time.
I looked everywhere on line for hydrometers for our year 12 biology students to use for their rocky shore assessment. This was the best value for money I could find.
