Please forgive my ignorance and lack of in-depth understanding of VLAN tagging etc...

We are on Vodafone FibreX, but running a Ubiquiti USG, switch and AP. 

I'd like to put all of the kids devices on a separate VLAN  (for a number of reasons, one of them being that I'd like to run their traffic through OpenDNS, without having to set it up on each device). If I set up a separate 'network' in the via the Unifi controller for this purpose, and tag it as, say, VLAN 55, would this cause issues with their internet traffic? I say this since I recall all WAN traffic is VLAN 10.

Forgive me if I am imprecise with my terminology, as I said, I am still getting up to speed with this stuff...

Thanks in advance!