Regard all details of instruction for use of manufacturer as well as shelf life of test kits. Some test kits must be stored in a refrigerator.
Use only test kits made especially for salt water (no kits for sweat water)
Measure always at the same time of the day, if possible at same water temperature and not immediately after feeding. Especially for testing ph, the time of measurement is important.
Water to be tested should be gathered always from the same position within your tank.
Measurement results of soluted trace elements of Calcium, Magnesium, Alcalinity are only comparable if measured at identical salinity
Use a syringe to gather the needed amount of water for testing accurately.
Clean and dry syringes, cuvettes, measuring spoons and covering caps after each use. Also don’t mix this parts between test kits
Gather your water to be tested as well as test kits chemicals without any air bubbles into the syringes.
To avoid unwanted dripping of dosing flasks, either:
a) Turn flask upside down away from the water to be tested
b) Slightly press flask whilst the opening is on top (some air will escape), whilst turning upside down. Then remove the slight pressure
Work tide, don’t have chemicals on your fingers, ..
Take regard to safety aspects (some chemicals are acid or alkaline)
Test kits needing to compare a certain color, should be done under natural light condition, but not directly in the sunlight. If measuring within rooms, always use the same source of light which should have an as white as possible spectrum.