What's the UV-C wattage. What are lamps made of such as low vapor? Besides this forum, what's the user experience with durability and leaks? Reefing unfortunately not the best for buying based on price because in the end it might ultimately cost more than penny saved early on.
Also, what exactly are you trying to accomplish? Pathogen or bacterial control? Can't do both without getting a large enough unit to handle the higher flow needed for bacteria only solved by more wattage at same flow to handle pathogens. That 25w anything isn't solving both for tank desired. Seems useless to solve bacteria and algae and better off getting adequate wattage at lower flow to perhaps reduce pathogens although eradication likely not happening and to be most effective need efficient filtration to reduce particles in flow entering UV otherwise pathogens get shielded by the dust and make the unit ineffective. Why I stopped using one in the 90s once this was understood and why future plans involve using it with proper filtration. Reducing the particles critical to ensuring proper operation otherwise just more wasted money on useless equipment that needs maintenance.