The plaster finish is meant to be underwater and not be used as a replacement to a tile border. The tile border provides a surface that can be exposed and also makes the water line easy to clean.

You can certainly find a gray tile.

Hi Mystic Pools, LLC. Thanks for the response. I understand that. Maybe my post was confusing. I understand I could find a gray tile but had read that darker waterline colors are more difficult to clean and had initially wanted the coping/waterline to be seamless. Also if the waterline tile is supposed to match the pool color, that was a struggle for me because of the changes between blue/green/gray. Have you ever seen a white tile with a gray plaster? Thank you!

Have not seen white tile I think anywhere ever on a pool. Only a tiled commercial pool and spa we serviced years ago. The white will definitely show dirt/scum line.

Generally a contrasting tile to plaster and coping looks nice. All 3 should compliment each other.

It's a myth about dark tiles.