Weevil

You need the Mirror Shield, which reflects sunlight to activate sun symbols.

First off, make sure you have the Song of the Storms. You can obtain this by using the Captain's Hat and talking to one of the Stalchilds circling one of the graveyards (I think it's on the Final Day) in the Ikana Graveyard.
Next, use this song to make the river flow in Ikana Canyon. Enter the music house (by using a bomb on one side of the house and hiding on the other side), and get the Gibdo Mask.
Now go to the well in the ground, in the upper left of Ikana Canyon.

To make your way through the well in Ikana Canyon, you must talk to the various Gibdos (with the Gibdo Mask) and give them items, most of which you store inside bottles.
Items such as: Hot Spring Water, Bugs, Blue Potion, Magic Beans, Milk, Bombs, a Big Poe, and Deku Nuts.
Most of these items can be found in certain rooms in the dungeon. A cow (which produces milk with Epona's Song) and the Big Poe are locating past the door to the right. Hot Spring Water can be found past the door straight ahead. Black Poes (hidden inside pots) usually drop Bombs. Deku Babas drop Deku Sticks and Deku Nuts, and Bugs are usually everwhere.

The main thing is to enter with a Blue Potion and Magic Beans (5?). There is a fairy fountain (to regain health) located north of the entrance, in a large room. The east-most room from the entrance has the cow. The other large room to the east of the entrance, close to the cow's room, is where the Big Poe is (there are Arrows inside the pots in the corners of the room). The mirror shield is north-east from the entrance.

Diamond Lucario

You need to reflect light with your Mirror Shield once you get it, or use light arrows once you get them.