Oh this pool was probably due for a new liner ten years ago when I moved in! I squeezed an extra decade out of it. I was bleached looking back then.One thing I should mention I would not patch large places with cement+mortar use vermiculite if you are going to patch. The patches that mine had fell out they did not stick to the vermiculite A skim coat of vermiculite may work. They say you can patch vermiculite with sand+mortar mine was subjected unprotected weather and may have been installed wrong. liners bleach out normally due to sun so I would just put it down as time to change the liner. Jimmy may be the pro
I have to read more about this vermiculite. I have done a little bit of work with cement before, so I am sort of familiar. When I Google vermiculite, I see a lumpy looking material. It would definitely add a texture to the bottom when the vinyl is in? The vermiculite is mixed with concrete instead of sand?