Loading... Please wait...This innovative product line combines regular and small size pebbles. The two pebble sizes interlock and create a tight compaction that gives the finish an even smoother texture than single-sized pool finishes. Glossy black pebbles make up this finish. The watercolor in most cases falls into a dark black bottom hue. The watercolor hue cast by black bottom pools can be either blue or green. Because of the intense color, they are highly influenced by their surroundings and sunlight.