▁stop ▁depth ▁at ▁the ▁recommended ▁rate , ▁and ▁follows ▁the ▁same ▁procedure ▁again . ▁This ▁is ▁repeated ▁until ▁all ▁required ▁decom pression ▁has ▁been ▁completed ▁and ▁the ▁diver ▁reaches ▁the ▁surface . ▁ ▁Once ▁on ▁the ▁surface ▁the ▁diver ▁will ▁continue ▁to ▁eliminate ▁in ert ▁gas ▁until ▁the ▁concentr ations ▁have ▁returned ▁to ▁normal ▁surface ▁s atur ation , ▁which ▁can ▁take ▁several ▁hours , ▁and ▁is ▁considered ▁in ▁some ▁models ▁to ▁be ▁effectively ▁complete ▁after ▁ 1 2 ▁hours , ▁and ▁by ▁others ▁to ▁take ▁up ▁to , ▁or ▁even ▁more ▁than ▁ 2 4 ▁hours . ▁ ▁The ▁depth ▁and ▁duration ▁of ▁each ▁stop ▁is ▁calculated ▁to ▁reduce ▁the ▁in ert ▁gas ▁excess ▁in ▁the ▁most ▁critical ▁t issues ▁to ▁a ▁concentration ▁which ▁will ▁allow ▁further ▁as cent ▁without ▁un accept able ▁risk . ▁Con sequently , ▁if ▁there ▁is ▁not ▁much ▁dissol ved ▁gas , ▁the ▁stops ▁will ▁be ▁shorter ▁and ▁shall ower ▁than ▁if ▁there ▁is ▁a ▁high ▁concentration . ▁The ▁length ▁of ▁the ▁stops ▁is ▁also ▁strongly ▁influenced ▁by ▁which ▁t issue ▁compart ments ▁are ▁ass essed ▁as ▁highly ▁s atur ated . ▁High ▁concentr ations ▁in ▁slow ▁t issues ▁will ▁indicate ▁longer ▁stops ▁than ▁similar ▁concentr ations ▁in ▁fast ▁t issues . ▁ ▁Sh orter ▁and ▁shall ower ▁decom pression ▁div es ▁may ▁only ▁need ▁one ▁single ▁short ▁shall ow ▁decom pression ▁stop , ▁for ▁example , ▁ 5 ▁minutes ▁at ▁. ▁Long er ▁and ▁deeper ▁div es ▁often ▁need ▁a ▁series ▁of ▁decom pression ▁stops ,