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Hydrangea cultivars can be very hard to ID--the flower color varies with soil pH and will also change as the flower ages. Then factor in different cameras/lighting and it becomes next to impossible to say for sure what it is. I looked at the picture of Sandy that you linked to, and I think either the bloom is aging or the color is weird because of camera/lighting--I think a fresh bloom grown in alkaline soil would have a color similar to yours. I'm having trouble finding other pictures of Sandy to compare yours to, so I couldn't say for sure one way or the other whether that's it or not though. Your best shot at an ID would be if the tag lists the grower, see if they have a website that lists the other cultivars they grow and maybe you'll see one that's a better match.