How would we acheive this color? I asked my pool contractor about white concrete and he said all they can do is leave it uncolored which would look more gray than white.

It is white concrete. Not the typical grey. More expensive but worth it in the right setting

Any professional fabricator will have access to White Portland Cement, not just Grey.

White costs us up to three times as much per bag in our region, but it won't raise your overall cost much.

Concrete fabrication is mostly based on labor. Even a high performance concrete mix would only have about 45% Portland Cement in it. The rest is sand, pozzolan, additives, and any needed reinforcement.

And as Sage Design Studios, Inc. stated, it is worth in in the right setting.