Test strips may be used to verify adequate levels (higher than 0.5 ppm) of iodine release

These tests strips are only to be used to determine the level of IODINE present in Dental Unit Waterlines (DUWL’s), and cannot be used to measure the presence of Colony Forming Units (CFU’s). Crosstex recommends checking the iodine level at 11 months, or as you approach 240L of water, to ensure that the iodine output has not fallen below 0.5ppm – particularly if you have a very busy practice.