that is fine. i just make sure it is fully dissolved before the fish come in contact with it. I lost a group of baby bichirs after I dumped in the undissolved salt. All of them were dead soon after with serious salt burns on their stomachs. I learned my lesson!
my husband like to mix it in water then gradually add the water in. I put the dose in a fish net and then hang the fish net in the top of the tank...the salt dessolves slowly into the tank.