When you get a bit higher in level the next best place to farm Balaur in the Upper Abyss is on Miren Island. Here you will find level 40 Balaur that are pretty easy for you to kill. You'll be fine killing all of these Balaur at around 38/39+. There is a "Klaw" type mob mixed into these, you can see them in my video. The Klaw mobs don't drop the goodies that the Balaur drop. Here you will be farming for the following items:
Cold Balaur Blood Stain
Thick Balaur Horn
Tough Balaur Meat
Vicious Mind of Wrath
These items will net a pretty penny for you on the AH, that is of course if you don't use them for your own crafts. In addition to the items listed above the Balaur will also drop some extra Kinah. These Balaur are also the highest level Balaur for you to farm in The Abyss.