I have a poured concrete shower pan that's tiled. I then have durock walls meeting the base of the pan, also tiled. The grout is letting water leak through the edge where the durock meets the pan. I've ground out the grout but I'm not sure the best material to put in there to seal it. From reading the web I've heard suggested regrouting and using a good grout sealer, using silicon and even someone mixing two part epoxy with a quartz filler. Anyone have a "best practices" solution? Thanks

Were you actually getting water dripping down somewhere in the home? That pan has a lip that goes up behind the tile and should stop any leak. Do not grout this edge, it moves ever so slightly so it needs a bath caulk like Dap Kwik Seal. You can get it in many colors to match your grout closely

Thanks for your response.
Because it's a poured concrete pan, there is no lip. The durock sits directly on top of it and the tile goes up the wall and on the floor. It's only the material in the joint that seals it.

As an addendum note, it's also been suggested to use hydrolic cement (water plug) as it's expandable and might seal it.

The last thing you want to do is introduce expanding cement between the cement pan and the tile, things are going to pop. This is a caulk joint, not a grout or cement joint