Just wondering if anyone here has had any experiences with UV
sterilisers. After having lost four discus in three days, I was
absolutely shattered. After days of large water changes, medication and
turning the heat up to 32 C, I'd rushed off to the LFS and asked the
owner if there were any preventative measures I could take to minimise
the spread of disease and parasites and he promptly showed me a UV unit
intended for ponds (Intensity 239). So I installed it and within 10 or
12 hours the fish were looking alive again. The discus that were near
black, changed to their characteristic colours, vibey and full of
vitality. Needless to say the water clarity had improved greatly.

I'm curious to know about your experiences, good and bad, and any
advice you may have to offer. 

Thanks in advance.