Hover over to the next small platform with the switch on it and step on it.  Turn around and use your hookshot to get up onto the platform and get the silver rupee you couldn't reach before.  Turn toward the middle of the room and Z-target and toss a bomb at the eye laser thing.  Hover over to it's platform then across to another silver rupee.  Hover back to the eye laser thing's platform and forward to the one under the door.  Now wait until the fan to the right of the door stops blowing then hover across to the last silver rupee.  Go through the door and shoot the floating ball with a Light arrow to be warped back to the main room.

Head right again and go through the next door, the Water Barrier.  Empty one of your bottles (NOT a blue potion) and use it to get some magic blue flame from the center of the room.  Walk around the room to find the two ice statues and kill them to unblock the door.  Melt the ice blocking the door with the blue flame, then refill the bottle with more blue flame.  Go through the door.  In this room, push the ice block furthest from you right, then back (toward the door you came in through) so that it falls down the hole.  Then push the other block right, forward, and finally left so that it ends up in the nook in the wall.  Climb up it and use the blue fire to melt the ice.  Smash the switch with the hammer then go through the next door.  Kill the floating ball thing with a Light arrow and you're back in the main room again.

Continue to the right, past the Shadow Barrier door since you already beat it, and on to the Fire Barrier door.  Equip your Hover Boots and Goron's Tunic.  Collect all the silver coins in the room.  Watch out because most of the platforms sink in the lava while you're standing on them so keep moving.  There's one on the platform with the rotating fire-breathing statue and one just to the right on a block.  Further down on the left there's a big pillar.  Lift it with your Golden Gauntlets to reveal another one.  Then the last two are on the far right side of the room.  After you've grabbed the last one get close enough to the door so that you can hookshot to the hookshot target next to it.  Go through and kill the floating ball thing with a Light arrow and warp back to the main room.

Once again heading right, move the pillar out of the way of the door to the Light Barrier.  In the first room, use the Lens or just Z-targeting to kill the 4 bats and big skulltula in the room.  Get the key in the chest that appears and go through the locked door.  Use Zelda's Lullaby in the next room for another key and go through the locked door.  Now you're in another collect silver rupees room. There's 2 in nooks on the outer wall, two in the structure in the middle, and one on the ceiling you can get with the hookshot.  Go through the door and...the ball thing is missing!  But not really.  Go straight through the wall in front of you and you'll be in the real room with the ball thing.  Destroy it and warp back.

On to the final door, the Spirit Barrier.  In the first room, once again collect silver rupees.  Blow up the eye laser thing with two bombs or bombchu's.  Just roll attack (forward+A) through the spikes to get most of them.  Don't forget the one floating in the middle of the room - hookshot to the ceiling to get it.