Ah! Tru-D......gotta love her sweet blue glow! Well, that's very high level UV for sure....and its done after a standard terminal clean, right? The UV lights sold for residential pools are very small in comparison. The water that flows over the light may be cleaned but the rest of the pool water has no beneficial residual effects from that small UV light. So you still need chlorine- why pay for a device that's undersized and just chews up chlorine but doesn't really protect the pool on the whole??Not to hijack the OPs thread... but is the efficacy of breaking down viruses with a UV light same as the atmospheric UV rays? At the hospital I work at they "disinfect" rooms/equipment by bringing a UV light cell into a close room for like 30 min.