This forum activity requires about 16k - 20k.
A lot of people say that you require 20k but this is not true if we consider how active this forum is.
The 20k is a rule set for super active forums that get 1000 thousand upon thousand in less than an hour, the Overwatch (and maybe WoW) forums fall into that category, the actual requirement is to read 25% of the amount of posts/topics that were posted in the last 100 days so if we apply math when it comes to how much the OW forums get posts, you probably need about a million being read and keeping that up in the last 100 days, to avoid that, there’s a cap, this is where the 20k comes to mind.
For smaller communities probably need less, if a forum gets about 1 post a day for the next 100 days, you need to simply read 25 posts out of the 100 and you simply can check mark that requirement for the next 100 days. 
So as I said, I would say the requirement here is far less, I would guess its 15k - 16k for HotS US forums.
Although keep in mind you need to keep it up, since from looking at your profile that you joined early, I would suggest try working on your daily visits, as you need 50 day visits in the last 100 ddays.
A sign of Trust Level 3 is having this wrench option:
You can also check your trust level through checking your json file, made a guide about it:
or simply use this site to check on all Blizzard Forums (does the same thing you would do when it comes to checking your trust level in json file)
https://trustlevel.000webhostapp.com/
Made by MVP Pachimari.
More info about the requirements can be found here: