I'm sure there is an easy answer to this... but for the life of me I'm not sure what to use.
I'm trying to prevent the tiny grout cracks along the inside wall of my spillway from letting water through. Picture this:
I have a flagstone spillway from my spa to the pool. The top of the spillway is 12" wide surface of flat flagstone that is bonded via concrete to the gunite structure underneath. On the inside of the spa is tile and between the top of the tile and the bottom of this flagstone surface is grout. The type of grout used to fill the gaps between flagstone pieces tends to get tiny cracks. These cracks are causing seepage.
I don't think I can use typical concrete/stone sealer as it probably won't fill the cracks and make the area watertight. I'm thinking that something more sticky and pliable would work... like even silicone, but not sure what to use that'll stand up to pool chemicals. This is a "hard to see" area and any material that is dark grey in color would work great.
Any suggestions? It's a problem for me because I'm getting calcium buildup from the slow seepage.