UV works early morning, late evening or down deep.
Glow works deep or whenever it's overcast etc.
This particular flasher has:-
GLOW
UV
and Green/Blue are two colors that show up well throughout the water column to depths of over 200 ft.
Flashers will sometimes spook fish....no matter WHAT color they are.........
For huge fish I know guys that don't use flashers....they just tow a big herring by itself and that's it........
I have found that some flashers work way better than others for attracting fish.
One being the Super Gold Betsy.
I have fished certain tackle with several flashers and don't get hits.
I then put the identical tackle behind a Super Gold Betsy....and I start getting fish.
After about 6pm I switch to flashers that have more Glow on them. Once the sun starts hitting the water at a steep angle the light down below falls off pretty quick at depth, even though up top it looks fairly sunny out still.
Mirror U/V finishes tend to reflect several colors to the human eye depending on which way the flasher angle is reflecting the light (like when you have it just about at the surface)......I wouldn't lose any sleep over that........
There are "quiet" flashers....and there are "aggressive" flashers (in terms of finish and colors etc)...........up shallow you might not need to go with an "agressive" flasher" so much.......(one that has eye-blinding color combos with a flash that looks like a nuclear explosion....
).......on the other hand , down deep there isn't much reflective light, so you you might need to go with something stronger in "attitude"........
If it's a dark day you might need more flash/color
If its' really sunny maybe not so much.
Green haze, Purple Haze, Glow Army Truck, Super Gold Betsy, Boogieman, Green/Glow......these flashers seem to work everywhere consistently......