Hi Rose, welcome to TFK!
Although some fish enjoy a good current, many, if not most, do not and it forces them to 'work' very hard to even remain still. This can be very stressful for some fish.
Like the use of activated carbon, most folks here by consensus see little need for a UV sterilizer. Although they can be very effective treating an algae problem, many would suggest that the root cause is elsewhere (nutrients and lighting). If you can't reduce or redirect the flow, you might consider not using it at all.