I have used only I/O since the mid 60's until I came to work here we use a special blend that is assayed and certified every batch and its a a great salt first I have ever used other then I/O I have set up systems using about every brand there is But not in my tank (: We have this here blended for more Ca and higher Magnesium and Strontium..And we had them to change the blend now for more carbonates I was not liking the low carbonates levels and having to jack the DKH up to my preferences after the fact.. If anyone would like to try a sample ? I'll send you enough for 5 or 10 gallons for just shipping cost . we may make it available for sale ? Its certified by the new england something or other Amcarrig may recall it ? the cost is very pleasing as we buy it by the pallets and every 25 boxes have the assay certified stamp and a contents sheet on it.. We use it in all the systems we install and maintain . Found the info New England Bioassay, Inc.
They certify all of the salts we use
New England Bioassay, inc. provides high-quality acute and chronic toxicological test services. These are not the people who mix the salt though we just have them to check to see its what we are paying for. It all looks the same to me.