Four kits in one! Tests for magnesium through a titration based procedure in increments of 12.5 mg/L. Tests for carbonate alkalinity, borate alkalintiy and total alkalinity in 0.1 meq/L resolution through a titration based procedure. The kit resolves borate from carbonate and, along with magnesium, this presents a clear picture of the tank's buffering capacity as well as a very reliable determination of the critical carbonate content required for coral and coraline growth. Each kits can perform 75 determinations for each test.