No. Don't use it at all. Your salt mix should set the proper water parameters for water changes...be sure to check it though...salt differs some from one batch to the next. Check pH and alk if nothing else. When you top off, use straight RO water with no additives unless you want to dose kalk. When the water evaporates, all the minerals are left behind...only pure H20 leaves the tank so only pure H20 should be added back in.