I did a ton of research on UV
systems before buying, ended up with a Vecton V2. They are brittish and hard to find in the states, but there is a place in Florida that sells them. (shoot me a PM if interested, not sure how this board is with posting links to suppliers) Also heard a bunch of positives on the life aquatic systems.
Either way, you want to focus on dwell time vs watts, or how long the water stays in the uv
chamber and how much uv
is absorbed in the process.