Dquixote1217, as per your past recommendations, I took the liberty of testing Utopia-Silver samples from two different sources in the not-so recent past, only to find that the product did not measure-up to its DYI counterparts. In short, it was my observation that the product proved inferior in both; antibacterial and low pH persistent applications.
Now, to be fair, I'd add that this is not to say that Utopia-Silver was any worst than other competing product on the market, in that, many(if not most), of the products in the testing performed quite poorly against what we'd call freshly made CS. And where Utopia-Silver's performance was on the upper-end of the scale in terms of purchased solutions. Though it remains that its performance was about equal to a 10ppm DYI solution. Which in my opinion, it simply not worth buying against a well-made home brewed solution.
PS. You may also be interested to know that Mesosilver proved worst than Utopia-Silver in most all of the performed tests. And that Utopia-Silver's advantage appears to be its ionic content - if that's of any interest to you or your partner.