Submerged Chest

Submerged Chest
Submerged Chest treasure is located in Zereth Mortis zone
Treasure is located underwater
Collect Dangerous Orb of Power on the ground to the south-west of the treasure near the wall.
You will get the Unbearable Power buff
Use Forgotten Pump above the treasure chest
It can be inactive (someone has probably used it before you), just wait near the pump ~5-30 mins
Submerged Chest treasure is a part of Treasures of Zereth Mortis achievement.
Reward is Admiral Pocopoc & Spatial Opener

/way 59.41 76.81 1 Collect Dangerous Orb of Power
/way 58.62 72.91 2 Use Forgotten Pump
/way 58.73 73.01 3 Collect Submerged Chest
Submerged Chest video: https://youtu.be/Dzc1jM5ldGo