About: http://webisa.webdatacommons.org/253625663

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	As stated above, although you only stayed for 30 minutes at 50 feet on the second dive, you need to add the 31 minutes of residual nitrogen you still had in your system, i.e. 31 minutes.
http://www.w3.org/ns/prov#wasQuotedFrom	scubadiverinfo.com