Insta-Test Big/Alk/pH/Th Test Strips are used for testing pools and spas using a biguanide system eg Aquaspa.  Featuring an easy to read colour chart these strips are simple to use.  Just dip the strip into the water and read. The bottle has a moulded desiccant liner, which protects the strips from moisture and UV light. Test for Biguanide     0, 15, 30, 50, 80ppm Alkalinity      0, 40, 80, 120, 240ppm pH                    6.2, 6.8, 7.2, 7.8, 8.4, 9.0  total Hardness    0, 100, 250, 450, 800ppm Directions for use Immerse strip in the pool to elbow depth for 2 seconds.  Remove with pads face up. Shake once to remove excess water.  Wait 10 seconds and compare to colour chart starting from the top and working down. For spas, turn off jets before testing. Important Tips For best protection, test twice a week Store strips inside the home, away from extreme heat or sunlight To open cap, push tab up with thumb and carefully pull out a strip Avoid wet fingers inside the bottle and close the cap tightly right after removing a strip.  To close cap, press the centre of the cap down firmly until it snaps Bottle contains 25 test strips.