This pack is Nitrate, Nitrite, pH and Ammonia.
This kit will allow you to test for every main tank cycling parameters for your reef tank.
Nitrate and phosphates you want as low as possible .While Calcium Alk and magnesium need to be as stable as possible .
Nitrate aim for below 5ppm
Ammonia and Nitrite need to be at 0 (unless you are cycling your tank).
pH needs to be around 8.3