"Paul" wrote in message
...
If you have the UV running and trying to start a new filter the UV will
kill
all the bacteria you are trying to cultivate to do the biological
filtration
of the water. The UV should be turned off for at this a week or two to
let
the culture grow and you may find you never need to turn it on again if
the
filter traps all the fine particals

But if you UV before your bio-filter, or after...doesn't that avoid the
problem of killing your biomass? I thought UV was only detrimental to your
biofilter if it is in the filter.

BV.