Will a sand color pool liner make the water look like Caribbean ocean water?

A sand-colored pool liner will give the water a light blue-green hue, but depending on your pool's depth and lighting conditions, it is unlikely to create the exact visual of Caribbean blue sea water. Caribbean colors and hues come form a complex variety of elements like depth, lighting, sand composition, underwater ecology, etc. Pool liner's sand color only gives a hint and not completely replicate actual Caribbeans hues.