No Golden Mom. I thought I was clearer about that. I’m sorry. It’s not determined by if you can see it but if it is visible. The idea behind bug lights is that most of us do not have perfect vision and so we can’t determine ourselves what is visible to the naked eye. ‘Visible to the naked eye” means by a normal person (presumably 20/20 vision) who is actually looking, in normal daylight. If it could exist that there was a bug that is only visible through a bug light but would be too small for any person to see without one then such a bug would be Muttar. A light just helps us see what we can see anyway, it doesn’t make smaller things look bigger.
About the water in certain areas of New York: first of all, not “all the Rabbonim” said you need a filter. There are many notable, valid opinions to be Meikel. Those bugs are visible without a microscope (I have seen them myself) they just are very hard to see, especially when they are dead and not moving. We once took a trip to a reservoir; you can really see them swimming around in there. They are very light and almost see-through, but they are visible (to me, at least) if you look closely enough, especially against a black background.