Heroic Dungeons

[FinalxxSin]

I noticed dungeons are divided into 4 difficulty tiers.  My simple question is this: Are Heroic dungeons not meant to be done solo when you have less than a 5 level advantage?  For example I went into the Blackram Narrows with my Assassin lv. 21 and got totally annihilated by the level 20 enemies.  Is this normal for this tier, or do I just need to "get good"?  

[zRUKIAz]

yes, you don't suppose to solo purple dungeon like ever at recommend level. 

[FinalxxSin]

5 minutes ago, zRUKIAz said:

yes, you don't suppose to solo purple dungeon like ever at recommend level. 

Thank you for the help.