I made one years ago designed the same way as a lieberg condenser. I used a three foot UV flouro tube and a PVC pipe as a jacket with a smaller inlet and outlet each end. There are problems with UV sanitizers which have to be addressed. Water clarity, water depth, keeping the tube clean and operating temperature as well as contact time are all critical. I would doubt that an led would give out enough light. I used mine on sea water and siphoned water from a top tank to a bottom overnight (very slowly). I made it from a piece of the pvc pipe by your front gate used by telecom for wires and an end cap each end with the tube held by rubber bungs. It worked well but needed clean water and frequent cleaning. The flouro tubes are for UV sanitizers and are not cheap (or were not then anyway)