Question about Intex Whirlpool PureSpa Jet & Bubble Deluxe Massage

We have received the pool, everything worked out great, it was not exactly easy at this particular time. I have a question for the professionals who are already using the pool, I would like to use sea salt, but it usually has residues with shell particles and sand purity 99.3! Does anyone know where I can get some good ones? The dishwasher salt with 99.9 would be a good temporary alternative, wouldn't it? Thank you very much for an answer.