If adding
kalk and
Ca you definately need to test for alkalinity as well as the
Ca test you already have.
Alk and
Ca need to be >>
balanced<<.
GH is not the same as
KH.
GH measures the combined parts of
Ca and magnesium and does not need to be tested in a
SW tank.
KH (AKA DKH or mEq/l
CaCO3 equivalents) measures the total amount of hardness within the system and is very important.
Strontium is rarely a needed addition and simple water changes will take care of that. Nothing in your system will require it's addition. If nothing else, get a test kit to monitor the levels. If Sr gets too high it can be a problem and will actually interfer with certain test kits such as
Mg.
Iodine is another not really needed addition unless you have animals/algaes in the tank sucking it up in large numbers. As before, be sure you are testing for it. Most tanks don't need it or at least much less than you think.
I would also suggest you get a pH test as well.
Mg can be an important component of the chemistry but is easily maintained with regular water changes. If you ever have issues maintaining the balance between
alk and
Ca you may need that as well.
Cheers
Steve
