If you’re someone who doesn’t need a full on kit to help you out (maybe you’re no beginner to reef or freshwater aquarium test kits), there is the option of aquarium water test strips that take out a lot of the hardware when it comes to testing for simple, quick results for those who have done this sort of thing before and know what to look for. This kit still includes instructions and even has a second booklet to help you correct unsafe water conditions, should you come across them.
Aquarium Water Testing Kits - YouTube
This test kit reads total nitrite (NO2-) level in parts per million (ppm) which are equivalent to milligrams per Liter (mg/L) from 0 ppm to 5.0 ppm, in either fresh or saltwater aquariums. Other nitrite test kits that measure “nitrite-nitrogen” (NO2-N) will give readings 3.3 times LESS than this test kit.
This is just a general video about aquarium water testing kits
Conditions in aquarium water naturally change over time, so it becomes necessary to regularly test your tank water to make sure it is healthy and stable. Bulk Reef Supply sells a variety of test kits to best fit your needs - Elos, Red Sea, Salifert and Elos master test kits that include essential tests for your aquarium type: pH, hardness, ammonia, nitrite, nitrate and oxygen — all necessary factors to that need to be maintained to ensure a healthy and thriving tank.
Salifert Water Test Kits for Freshwater Aquariums - Marine Depot