Once you have the test results then you will have a guide. I was like .01 so I added 4 drops. I then added 2 drops next day for a total of six. Waited over night and retested and was .06. And the zoas openned up .... I dose iodine once a week with two drops total. I am going to test today my iodine tank level and fresh fritz salt water and will post the results. When you use that test kit you must temperature aquamate the reference sample. Just follow directions. Also, the jugs I use for water changes are attached.