Many saltwater aquarium fish, corals and inverts are constantly using oxygen (o2)in your tank,The Bacteria needed for to maintain proper levels in your biological filter are also using O2 at an alarming rate.
It is vital they you are giving enough oxygen to maintain health 02 levels in your tank. To make sure these levels are maintained at a constant level you should monitor your water parameters for properr dissolved oxygen levels with the Hanna or Milwaukee's Dissolved O2 meter.
The Hanna O2 meters will all you to measure with precisionthe oxygen levels currently in your tank.
TheMany Hanna O2 meters reads form 0-19.9 ppm. Accurate to + 1.5%, you can trust the digital reading from this system Monitor your aquariums O2 often, levels can fluctuate daily, due to many changing circumstances within your tank's bio-system.