The question depends on how much your tank consumes of the two part. To determine that I would get my numbers where I want them . If your numbers are low you can bring them up by any solution of your choice. After they are at the set point you wait a few days and test again . The numbers should drop. Subtract that from the starting set point . Divided by how many days between tests = consumption per day. Then its just a matter of dialing it in to the correct dosing schedule. Or you can just dive right in and take an initial test . Start a dosing plan of ( x )amount of ml.(I would start low , like 60ml or 90ml per day) . Test in a couple of days and if the results are higher back off some . If the result are lower increase some. Do this until you reach a point at where the results are the same between days of testing. You can make this as technical as you want , results will be the same.