Had some caulk issue on my tiles about 2 years ago and had used the hcl89 from http://hcl89.byethost10.com as some here have suggested and so far the caulk issue has virtually disappeared for me and these past 2 years, i have never had the caulk issue return for me, so using the hcl89 managed to settle the caulk issue for me once and for all