UV sterilizer when to add one

[Acronuts1]

:bounce2:I wanted to know w/ my new 180g when will be a good time to add a uv sterilizer?
The tank has been running 2 wks but has most of my old water, old LR, and about 50% of the old sand.
I figured I could start at around the 5th week. Why? Well I thought that the uv would not be selective in which bacteria it zapped. Adding too soon might kill beneficial bacteria that I may need right now.
What are your thoughts?

 

[WRASSER]

mr. jj,
the uv will kill all things, good and bad. for fish only that is ok. but for corals it is not. the uv will kill the good stuff that the corals need.

 

[Acronuts1]

I see your point!
How are your fish doing?

mr. jj,
the uv will kill all things, good and bad. for fish only that is ok. but for corals it is not. the uv will kill the good stuff that the corals need.

 

[WRASSER]

ummm so so, lost some and replaced some. all is well at this time. ty