Salifert Boron Test Kit. Boron is very important in marine environments. Too low a concentration can slow down the growth of corals and calcareous algae, and too high a concentration can result in a build up of boric acid which can act as a bactericide, killing essential bacteria. Concentration in natural sea water is relatively low, between 4.4 mg/L and 4.8 mg/L. Monthly boron testing is therefore advisable. The Salifert Boron Profi-Test kit measures the level of naturally occurring boron in steps of 0.5 mg/L. Sufficient for up to 25 tests.