WoTLK Halls of Stone Boss Strats

Krystallus

All party members should stay spread out from one another and tank Krystallus towards the top of the ramp, but not at the exact top of it. He will toss the party up into the air and throw them in a random direction that can't be controlled. As soon as you land, the party should try to move away from each other as fast as possible. After a few seconds, everyone will become stone and Krystallus will shatter them. If any party member is near another, the damage taken from shatter is increased, making it very important that everyone stays spread out to reduce the chances of more than two people landing on top of each other.

Maiden of Grief

The party should stay spread out near the doorway to begin and Maiden should be tanked in the middle of the room where she stands. She will create a large void zone periodically and anyone in it should move as fast as possible away from it. Maiden also has a stun ability that breaks when damage is taken, but it doesn't stun the entire party. That is why everyone must stay spread out to make sure that not everyone becomes stunned at the same time. Any storms that she creates should be avoided and can be moved away from if she casts it on top of you.

Sjonnir the Ironshaper

Sjonnir should be tanked in the middle of his room. He will summon oozes and iron dwarves to his side that should be picked up by the tank. They have relatively low health and can be easily killed by the dps. He will continuously cast Lightning Shield on himself that should be removed if possible to reduce damage done to the party. He will also call down a lightning ring that will cause damage to anyone standing near it or in it that can be moved away from. His most threatening ability is Static Charge and should be watched for specifically. When a party member gains this debuff, they start causing aoe damage to anyone near them for 10 seconds. It is very important that all party members try to stay spread out from one another or at least have the person with the debuff to move away in order to reduce party damage.

Taken from mmo-champion.com