Red Sea 4 Part RCP Lrg 600LProduct Description Meet the new 4 part Complete Reef Care, providing hobbyists with more convenience at no extra cost, and ensuring optimal coral growth and vivid colors with only one test per week! Our long term research has revealed that in most reef systems without refugium, the Major, Minor, and Trace elements and even the Alkalinity components are used up in a relatively fixed ratio. Since Calcium is the key indicator of coral growth, the 4 part