Well that would depend on your knowledge of chemistry. For example to add iron to the water one brand may use one iron salt while another may use a different one and it may interact with the potassium salt of the other brand. You won’t find the exact salts they use and while some are likely the same not all will be. Thus some salt mixes have a sulfur smell when mixed while others do not. That smell is a difference in the salts used to make the mixThis doesn’t make any sense to me. My guess is that there will be no issues.
But, I am doing a water change today and will make water with a 1:1 ratio of Red Sea Blue bucket and Tropic Marin Pro and report back.