Yes they can and this has been discussed on this board, but was a good while back. However I bet if you do a search on here you will find lots of good info. I am sure I have posted a good bit on it. Florescent colors also do the same thing, but maybe not quite as far away in perfect conditions of super clear water. I subscribe to if one uses FL colors they don't have to take the extra step to go with UV, unless it's a color you can't get in FL and then it should make a difference, just not sure how much.

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