salt

I recently purchased a 150gallon rank fully setup and stocked with fish and corals. The tank came with what little salt the guy had left when he sold it. I have been using this salt for water changes and to replace the water lost during the move. I have just ran out. I went to the LFS to buy more and they do not carry this particular brand. And it would be a special order. The price would be almost one and a half times greater to get the same as what I have been using. My tank is doing wonderful and I am trying not to screw it up. Would it make a big difference to switch? The salt I am using is aqua vitro salinity. I am thinking about switching to tropic marin.