Iodine is always present in natural sea water, and is a vital trace element for many sea creatures, it defends against diseases, detoxes the water, and provides a level of UV protection. This expert Iodine Test Kit from Salifert is ideal to accurately test for the levels within your aquarium.
Iodine is naturally consumed by marine life, so must be measured and replenished as required. Weekly testing will highlight any problems and allow you to dose accordingly.
Salifert have designed this test to test for iodine and iodate, whereas other manufacturers just test for one or the other.