Hello Pete,
NO. This is not the correct O-Ring for the filter dimensions that you provided.
Our Item ID# 362 is the correct O-ring and can be found at this link
https://www.wahlwater.com/O-Ring-Pentek-Big-Blue-151122-_p_378.html
As for the UV Lamp (Bulb) for your S8Q-WHS this is our Item ID#19 and can be found at this link
https://www.wahlwater.com/Viqua-Sterilight-UV-Lamp-S810RL_p_9.html
Please contact us if you have any additional questions.
Jeff - Customer Service