Regular testing of your water parameters will be required to ensure your aquarium and marine life are in optimal health at all times.
Testing acts as an early warning system for the environment your marine life live in; it will tell you if there is a problem somewhere and give you time to act before it gets worse. This is especially true for smaller aquariums where things can change very rapidly because of the small volume of water present to buffer any changes.
Regular water testing can easily save the life of all your marine pets.
Things are much simpler for marine aquarists these days than they used to be and every parameter can be easily and quickly tested for using test kits and testing equipment which will tell you exactly what is going on in your aquarium.
Remember to log all your results in an aquarium journal to keep track of changes over time. This will teach you how your aquarium is functioning so it becomes predictable and you can anticipate any changes.
A regular testing routine will alert you to potential problems with your marine aquarium, prevent disasters and enable you to maintain a pristine environment for your marine life.