I love crystal sea! The good stuff, not the stuff with the de-chlorinator in it. My friends at HoldfastAQ use it and they spawn muscles and oysters with it and use it for their Phyto strains that you can't kill!
https://www.holdfastaq.com/store
So like someone said, probably the water of your LFS.
BTW, as a disclaimer I use NeoMarine now.
Also, The feeling you are getting from IO/RC i the fact that it is a enriched salt mix.
Just like the Maddog 2020 enriched wine you get at the liquor store, there can be consequences...