I have the same problem! Same size HT, same brand, PH a hair low (7.3) and Alk lower than it should be (30ish). When I add chlorine, you'd think it was dishsoap! The foam is insane! I am not using 'splashless' bleach (like it's even possible to find bleach at all these days). I'm using Pool Essentials chlorine. it's 10% hypochlorite and compatible with salt systems. But the foam is just outlandish. I have a dedicated suit that does not get washed with soap, so that's not the cause. I just don't know what *is*. Any thoughts?