Finally heard from Instant Ocean Customer Support this afternoon - here is there response to my inquiry about and "bad batches" of salt....
Hello Ken,
Thank you for contacting us. We have no reported “bad batches” of either IO or RC on record. It would take a minimum of 3 complaints on a batch to require an investigation and no such investigation has been called in recent history.
Best Regards,
Consumer Relations Lead
Spectrum Brands|Pet, Home & Garden