"George Patterson" wrote in message news:_cFGh.558$3i.295@trnddc01...
Pszemol wrote:

Could you give me more details?

I started keeping marine fish in 1975. Those were the days of the undergravel
filter, and the use of powerheads was hailed as a great advance by my friends

I am afraid we misunderstood each other.
I was hoping to hear about details of your scientific experiment and
you are giving me details on how you kept your fishtanks...
This is not what I was asking about.

To really tell how UV influences fish/ich you need to have controlled
group of fish without UV in the tank and expose both groups of fish
with the same amounts of parasite...

During the experiment you would need to actually measure water
flow through the UV lamp estimating UV exposure time for the
disease organisms have some detailed data on fish infections
with real dates and real numbers...

If you do not have all this than your statements are based on anegdotal
evidence or no evidence at all rather wishfull thinking instead.

And it really does not matter if you have tanks for 25 years or 2 months.
Scientific method is much more important in judging how UV affects ich.