I guess I should shed a bit of information about Instant Ocean and Kent so that is no one else gets confused about who or which is a better salt. All comparisons to what salt is better is completely opinionated and studies are flawed. Just continue to use what works best for you.
It is a fact that KENT uses Instant Ocean as their base salt and then adds their extra suppliments to it so that it becomes their own. So issues you may have had are probably a batch issue and not a brand issue.