helping a friend out with a small issue on erosion of the white thinset/grout between the spaces of the wiremesh tiles at waterline. this is a very small mosaic pattern tile with small gaps between the individual spaces.
not consistently in all areas, but in some above waterline spots the white thinset (or grout) has been washed/dropped out and am wondering what is the easiest method of adding it back in?
Home Depot sells bathroom premixed grout/silicone/thinset materials and the easiest method I can think of is to locate a suitable white color grout mix that could be squeezed out from a tube and just lightly sponged into the spaces. This would have the added advantage of requiring no mixing and by standing in the water it may be entirely possible to avoid dropping any material into the water. I'm aware also there is a pool leak type of product that is also white and may be suitable for the same purpose. (there is no leak, the effort is purely cosmetic in nature)
the pool itself is in great condition so have no intention on draining water.
what's the best material in this situation?