The Finished Pool Tiles gallery is a useful guide to narrow down the look of colour you wish the pool tiles to look like. Its not a definitive guide as sometimes the lighting effect on glass tiles is not accurately captured but will be usually a good indication of what he water will look like.
Looking at the individual tile sometimes is deceptive as the same tile in a large area and then covered in water will look different. Generally speaking the colour tone will be a shade darker and then different types of glass tiles will have a different impact on the effect.