Totally stupid question he why do you use a UV sterilizer? Is this for
green water problems?

No. I got a UV sterilizer because I stocked my tank slowly, over a period of
months. I didn't have a quarantine tank, and didn't want to have to worry
about ich outbreaks, introduced by the constant stream of new fish.

A lot of people prefer UV sterilizers to treat or prevent ich and other
parasites, particularly if the tank is large. It can be a pain to medicate a
large tank, not least because you have to use so much medicine.

And some people like to use UV sterilizers just to keep the water conditions
more natural. Even the cleanest tank has something like 3 times as much
bacteria per ml as the dirtiest pond or stream. So a UV sterilizer can help
keep bacteria levels down to "natural" levels.

A UV sterilizer is certainly not a necessary piece of equipment. If money's
tight, you're better off spending it on substrate, lighting, or a good filter.
But it's a convenient thing to have, if you have a few bucks to spare.

Leigh

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