I have repaired several leaks this year where the gunite meets the drain. I use two part pool puddy and it has worked great. What are some products you use underwater ? The only problem I have with the puddy is that it only comes in white and black.

Tints-All, works well to create any color epoxy putty needed, you will need to practice blending colors to create the shade of color you need.
Also Anderson sells A + B in Tan, Black, and White, mixing allows various color shades to be made. Pro-Poxy epoxy putty is slate gray and is easier to darken with tint or lighten by mixing with white epoxy, it is compatable with Anderson's epoxy.
Bruce
poolrepairdiver.com