To me it's a fine tool to have. Part of my job once was measuring the effluent of uv filtered water to count colonies of bacteria and plate/enumerate them and report them to the usda
new bulb installation vs old bulbs due for replacement colony counts... Was required in bac lab certification for a beef processing plant, the point being they have measurable effects on water quality and paired with skimming do good for reef tanks. Uv debates are endless online no five people agree
But anything that has a history in aquaculture has validity. They do
Zoo exhibits
Labs
Research institutes for jellyfish larval tanks
They use uv for a reason
All the feed items like planktors they zap can just be fed as high quality frozen feed. People who do large water changes affect the bacteria just the same, via full export, it's not as if water polishing is bad...this is my case for uv if someone will bother to pay for one. I would use one if my tanks had pump setups like that as larger tanks do. Tanks can run without uv too, but they won't harm any coral and can help with cyano, diatom and dinoflagellate issues as a legit preventative. Am pro uv 100% buy an oversized one, one rated for double your gallonage this is like buying a car stereo we must not skimp
Must get on eBay and get two 1991 punch 45s and the tens as a minimum start, same is uv size it up for hedge