No, you do not. But you will need to add calcium, Alk, and magnesium by dosing regularly. Remember, stability is the key with SPS...which is one reason why people go to Calcium and Kalk reactors to maintain somewhat constant Calcium/Alk values....with little to no swings in water parameters.
If you dose 2 part additives get your hands on some used medical IV dosing pumps (check ebay) and have a constant drip into your system to maintain steady levels.....