As Stig indicate - the rules are not strict in Sweden. There is not any no or yes. Instead we have a bunch of rules that say that you should work constantly with safety and it is always one person responsible for the safety work. The work should be done of someone with enough knowledge and the one that is responsible is responsible for that the one doing the job have the knowledge he/she need. If nothing happens - the knowledge was good - if something happens - let us investigate . This is good in one way - the safety is rather high in Swedish workplaces - but consultants are not very keen to leave standards that have been established even if the situation is not completely the same. In this case - a public place (a pool) and in the other hand a workplace without public access (saltwater tank) But in this case - its better to go with the 36 V option IMO.
Sincerely Lasse
Sincerely Lasse