I'm not sure the more recent products have the severe side-effects I experienced, which has been limited to whatever product I used on that pool many years ago, and the Kem-Tek.

But it did surprise that I did not see any cloudiness -- even briefly -- from the Kem-Tek product. Initially, it made me afraid the product wasn't even working, so I was careful to do pre / post PO4 testing to reassure myself.

I should note that the product itself is a milky mixture, maybe like a water/skim milk mix. So when I poured it in, there was some haze from the unmixed product. But that disappeared as the product was diluted.