The slowdown compared to the 15-meter size was miniscule. In fact, most other people wouldn't even be able to notice the difference. However, Bai Xiaochun was so focused on the sea of fire that he could immediately notice the difference.
And yet, even with that change, the flickering colors within the 12-meter sea of fire were still impossible to penetrate with divine sense. Bai Xiaochun's eyes were bloodshot, and he was trembling physically from the exertion. By now, his cultivation base, his mental faculties, and his ability to shrink the sea of fire were all reaching the limit.
And yet, he didn't attempt to shrink the sea of fire down again. He tried yet again to find the eighteenth color. Then he tried a second time, and a third time.... In the short time it takes an incense stick to burn, he was able to glimpse it a total of fourteen times.