Advanced titration test measuring the level of Magnesium in your reef aquarium, with exceptionally high accuracy of 20 ppm Mg Red Sea’s MAGNESIUM PRO Reef Test Kit is an advanced titration test, measuring the level of magnesium in your reef aquarium to the exceptionally high accuracy of 20 ppm. The MAGNESIUM PRO Reef Test test kit enables the accurate dosing of Red Sea’s MAGNESIUM Foundation C supplement which is part of the complete Red Sea Reef Care Program.