The Salifert Potassium Reef Test kit is the latest chemical measuring tool from one of the stalwart test kit companies on the reef aquarium block. According to Salifert, the Potassium reef Test can be performed in about 90 seconds. This tritatic test kit has a sharp color change, going from yellow to blue, when you hit the level in the sample.
Potassium concentration in natural seawater is approximately 400 ppm.
Many aquarists have reported that a low potassium value reduces colors in Corals. This can be corrected by increasing the potassium value to the normal natural concentration.