The Red Switches
Head back to the Octorok Room and use Ice Arrows to freeze the Octoroks in place. Leap to the central platform and turn the red switch to allow water to flow through the red pipes, then return to the Central Chamber.
Swim through the upper opening to return to the Map Room . Now use the Ice Arrows to freeze the water where it sparkles and exit at the southern end.
In this room, lure the Blue ChuChu over to the red switch platform and freeze it. Defeat the Real Bombchu with your shield then turn the switch to allow the water to flow through the red pipes here.
Return to the Compass Room by taking the path with the Dexihands in the way. Across from the Real Bombchu is the path you want to take, it has stalagmites on the ground. Freeze the water where it sparkles then leap across to reach the Mini-Boss: Gekko Room.
Once again you must fight a Gekko but the battle mechanics here are very different from your first encounter. Mad Jellies fill the room and the Gekko will toss them at you as you pursue him.
Slash the Gekko and it will pull the Mad Jellies in to guard itself then drop from the ceiling, if Link is hit he’ll take a lot of damage. While the Mad Jellies are tight to the ceiling, fire an Ice Arrow to cause them to shatter upon hitting the ground.
Repeat the cycle four times to defeat him. Put the Don Gero Mask on and speak with the frog then exit via the door. Snag the Boss Key from the chest then use the Hookshot to leave this room.