lots of nonsense advice on UV lights.
the right way to use UV is to get a timer...presume yours is 4 footer tank ...let it run for 45minutes a day....daily.
yes it will kill the good and bad bacteria, but if your filteration system is good enough , the good bacteria will reproduce itself,...the main object is to reduce the bad ones.
45minutes will get 2 turnovers on a slow pump.
UV is not something to mess around with if u dont know have a full understanding of its fuction....skip this , most home marine tanks will do fine without it.

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