Flyguysc,I am not trying to be disrespectful in any way shape or form,But you might consider that there are 70 different compounds that make up the solution that we know as saltwater,some are [chelted] stays in the solution over a period of time,and is used as needed by organisms,and, some are [nonchelted] used up rapidly in the system,by the organisms,and do not stay in the solution ,,,,If you take hot water to disolve your salt you can actually mess with the chemical composition of saltwater.....Two that come to mind are calcium and iodine,And I would not forget about the buffering compounds that are also in the water .......I would just top off the tank with a solution of saltwater