An essential part of running a fish only or reef aquarium is taking time out to test the water on a regular basis. Test kits should be on hand at all times so one can pinpoint, and respond quickly if a problem arises.
Regular water testing will provide an important picture of the conditions the tank inhabitants are living in, and allow any problems that may be starting to arise to be rectified early. These saltwater test kits by Salifert & Tropic Marin are reliable & user friendly.