wˌɛn kəmbˈaɪnd wɪððə blˈuː ʌvðə wˈɔːɾɚ, ðə pˈuːl ɐpˈɪɹd təbi ɐn ɛksˈɛpʃənəli dˈɑːɹk ɡɹˈiːn tʊ ˈɔːlmoʊst blˈæk, hˈɛns ðə nˈeɪm.
When combined with the blue of the water, the pool appeared to be an exceptionally dark green to almost black, hence the name.