Recently I switched to Spark and I got Huawei HG630b router. In order to watch Netflix and Hulu I want to specify custom DNS servers (like Unotelly or Unblockus). I did specify those in routing page of the router and everything works. For a while. Then I loose connection to DNS servers. Talking to Spark it appears that my connection is just fine. Of course issue is that my streaming stops, loss of connection to game servers, etc.

So far I didn't find a way to change DNS servers displayed on one of main pages (I will post screenshots later today) and I wonder is this possible from UI at all. 
User manuals I could find on the web for Huawei HG630b don't have those details.

Any help is much appreciated.

Thank you.