UV sterilizers, to be effective, work on slower flow than ideal for a reeftank . Check how much flow do you need on yours particularly.
The SCWD is supposed to reduce the flow by 20%, but also requires a minimum flow to work. So if you have low enough flow for the UV sterilizer to be effective, I do not think your SCWD would work.
If you only want to use one pump, I would run them in parallel, but with a valve on the UV side to regulate flow.
BoricuaMojao