I have an in ground gunite pool that has a tile boarder around the top 6" or so. There are a few tiles that have fallen off over the years and I want to reattach them after I lower the water level for the winter. The tiles are mostly triangular shaped and only about 2" long on each side so they are small. The grout lines are less then an 1/8" so I figure I can use non-sanded grout. I went to Home Depot and looked at all the grout they had and none said they can be used for under water use. Some said they could be used in showers but not in constant contact with water. There were some that didn't say either way so maybe those are ok but I don't know what will work.
Does anyone have any experience with this?
In general you can use any grout for pools. Some may require an additional additive if it's outdoors though. Not knowing where you are or what brands are available to you I suggest you read some labels and check websites. Usually you have to not fill the pool for about 30 days after grouting in temps above 50.
I would rather use sanded if the joint is about 1/8", some even work well at about 1/16". I like Laticrete brand available at some Lowes and many real tile stores.
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.