Hydrometer - £15.99

Instant Ocean Hydrometer's new improved design  delivers precise full-range salinity and specific gravity readings - accurate to 0.001 - every time. Easy-fill convenience keeps hands dry when filling. It has a durable, permanent needle mount and easy-read 2-color scale with "safe zone" and an extra-wide stabilizer base. Ideal for use in water temperatures of 68 - 85 degrees F.