AquaChek's Red test strips allow pool and spa owners to test their bromine-based sanitation systems for total alkalinity, pH, bromine, and water hardness. Simply insert the test strip into the pool or spa water for 1 second, and seconds later you have fast, accurate results. It is recommended that you test your pool a minimum of twice per week, and spas before each use, to get an accurate picture of the health of your spa.