Proof?
If it such a bad salt, ask yourself why it is the most sold salt(by weight) in the world. Ask yourself why so many research facilities, and public aquariums around the world use it. Ask yourself why so many tank of the month and/or reef of the month tanks all have used IO.
I've used every salt on the market over the years, only thing that makes a difference, is the money that I keep in my wallet not falling for marketing hype, or peer pressure from fellow reefers that tell me my reef won't thrive without the expensive reef salt.
Send it to a lab and have it checked as I did
There are a ton of user on this fourm alone with the same reports
So before you attack someone go read and do some research io is one of the worst when it comes to clay
"Salt mixes start out by being mined from the earth, evaporated from seawater or refined from synthetic salts. They all can potentially contain impurities such as chelators, clays and clarifiers that will produce precipitate and brown organic crud on the storage tanks walls. Some aquarium salts can even create a brown foam on the surface, not exactly ideal considering the saltwater is supposed to be clean and ready for use in your precious saltwater tank!"
Quote from bulkreefsupply
And since there are 100s of user All reporting the same thing the lab I sent it to said the same
And I used io for 10 years with not great results since the switch I have had way better growth no brown crap and
Clay minerals are composed essentially of silica, alumina or magnesia or both, and water, but iron substitutes for aluminum and magnesium in varying degrees, and appreciable quantities of potassium, sodium, and calcium are frequently present as well.
So if you want this in your tank go for it I'll stick to what works
Not hype when it's tried tested and true