ESSENTIALS: MAKE IT SIMPLE Accurately test your aquarium's
salinity with a Portable Refractometer. Simple to use, optical
instrument gives a direct, temperature compensated reading of
specific gravity and salinity. Deep Six Hydrometer's unique
design takes true water samples for accurate reading. Instant
Ocean Hydrometer economically tests your aquarium's salinity and
specific gravity. Specific gravity measures the relative
salinity (amount of dissolved salts) in your aquarium water in
comparison to pure water. Measuring specific gravity on a
regular basis is crucial to maintain the ideal environment for
your marine inhabitants. The following helpful tips will ensure
accurate results when measuring specific gravity. - Most
hobbyists use a simple hydrometer or a refractometer to measure
salinity. - For professional results consider a portable
refractometer or a high tech electronic salinity monitor. -
Before changing your aquarium water, measure and record the
specific gravity. Make sure the new saltwater matc