Try playing around with a mix of Frost &? Flame on the Falmer. It also seems all Dwemer constructs are weak to Fire? and Lightning.
Here’s Revealing the Unseen Part 2.
In Revealing the Unseen Part 3 the key is found.
This is a side quest to find the Arch-Mage.
In this side quest let’s enter the Labyrinthian to find the Staff of Magnus
Part 2 of the Staff of Magnus quest.
Part 3 of the Staff of Magnus quest.
Part 4 of the Staff of Magnus quest.
Tip: The Morekei Mask and Arch-Mage Robe give you 200% Magicka regeneration, so you’ll hardly ever run out of Magicka.