Glass Tile calcium or tile defect?


New member
May 28, 2020
Marco Island FL
I have had 3 pools and familiar with water chemistry, cleaning, etc. I built a new house in Marco Island in 2016 and used 1 x 1 glass tile on waterline, waterfall, and spa. Over the last year, we have had significant buildup of what we believe to be calcium. We have tried everything to remove the material form the surface including (vinegar, CLR, dilute muriatic) but nothing comes even close to removing this buildup. I was not present when the builder applied the tile (this is my 2nd home) but confident they did not install a waterproofing membrane which i believe to be a significant factor in our current issues. We have decided to replace the current glass tiles and our pool company will be installing a membrane and replacing with new glass tiles. My question, will a membrane significantly reduce this type of buildup? Is there a sealer I can apply to the new glass tiles to reduce the build-up, and lastly - could our problem be a defect in the tile itself? Any thought appreciated!


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
Looks like efflorescence and it could be calcium silicate build up which can only be physically removed, not chemically removed. With glass tile, physical scrapping or blasting would almost certainly frost the tile.

If you are redoing the tile, then it's highly recommended you add the waterproofing membrane material to the gunite shell. You're doing that, so great! Laticrete products are always recommended here. See if the tile installer will use that. Also, don't use cement grout on the new tile, have them price out and use epoxy grout. Epoxy grout is hard to work with so the installer needs to know what they are doing and it will likely cost you more in materials and labor BUT epoxy grout is inert to many of the chemical issues that plague tiling in pools. With epoxy grout and good quality porcelain tiles (and the waterproofing membrane), you should not see any of the issues you're having now. You can still get scaling from the water and build up from splash and evaporation (ie, watermarks), but that would be far simpler to clean up.

Good luck, let us know what you end up with.