Our Coral Essentials – Boron Solution is a concentrated liquid boron additive, 50,000 ppm (mg/L).  Boron in natural sea water is in the order of 4-5ppm.  Boron is a component in the formation of coral skeletons, co-precipitating with calcium carbonate. Boron also assists slightly in pH buffering of aquarium water.  For the advanced aquarist boron levels in marine tanks should be checked regularly to determine the take up in your system.  Calculate boron usage by testing regularly, then simply calculate dosing requirements to suit the depletion rate.  Then continue a check of the levels every week or two.