Some of the most popular test kits available are the Red Sea test kits and Pro test kits. The Red Sea Magnesium test kit, Red Sea Alkalinity test kit, and Red Sea Calcium test kit are the most popular available. Red Sea tests are a great value when purchasing the Pro versions, giving you alot of tests with minimal expense. Red Sea Pro Kits are similar to a chemistry lab without the expense. They are a high quality test kit for your saltwater aquarium or reef tank.