Acting on a complaint by Cargill Inc., a national advertising self-regulatory group Thursday recommended that Morton Salt discontinue certain advertising claims for water-softening pellets, claiming the ads weren't adequately supported.

Minnetonka-based Cargill and Chicago-based Morton are the salt business heavyweights in the United States. At issue are claims made by Morton on packaging and on broadcast, print and Internet advertising regarding its System Saver II water-softener pellets, a salt-based product.

Cargill makes competing softening pellets under the Diamond Crystal brand.

After a review, the National Advertising Division (NAD) of the Council of Better Business Bureaus determined that the results of Morton's testing "were not sufficiently reliable to support unqualified superior performance claims (of System Saver II) targeted to the public."

NAD also concluded that Morton's disclosure on the back of its products' bags included confusing language and was inadequate to support advertising claims. Still, NAD acknowledged that for some consumers, Morton could support a more limited claim that System Saver II could improve a water softener's long-term performance and extend its useful life.

Morton, in its advertisers' statement to the NAD, said it will "modify or discontinue the advertising statements as currently made."

Mike Hughlett • 612-673-7003