What exactly is behind the term “routing” in your case?
IP-Routing on L3 - including inter-VLAn routing - is the Job of a Router, not a Switch…configure a trunk port to your Router and let that baby do the job.
Its called a “Router-on-Stick” scenario and is explained perfectly here: http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1
The CRS326 is, although being capable of running RouterOS, a Switch after all…unless you want to upgrade to latest ROS v7.1rc4, where hardware offloading of inter-VLAN routing on L3 has been introduced: https://help.mikrotik.com/docs/display/ROS/L3+Hardware+Offloading
But this version is not named a stable version, which is what I would consider using for a business scenario only.