High water flows trough the UV is better for bacteria
and viruses as they need little exposure for lethal
affect. Larger lifeforms have more UV tolorance and
thus slower flow would be better for them (or is it
worse?). It usually makes little difference as most
water born organisms would make several trips though
the UV and on the short term the affects are
cumalivtive.
You would need one UV for each centralized system one
didicated for saltwater.
If you do not use centralized filtration systems, you
may want to invest in a smaller unit and use it only
on tanks with problems on an at need basis, and adjust
the water flow level in accordace to the agent you
need to control (virus vs achorworm, High flow for the
former, low for the latter, though personally for
anchor worm I'd nuke the tank with potassium
permanganate, followed by bleach. The UV would work,
but it would not be compleatly effecient and would
only be treating the water born egg and larval
stages.)
The best units are the ones with Stainless steel
chambers. The ones with PVC chambers get burnt over
time (literally) and start to release small levels of
toxins into the water. The second benifit of
stainless steel chambers is that the metal is
reflective and thus intensifies the expouser.
There are bad points to UV. It will reduce the levels
of benificial water born bacteria. However in
established systems most of these bacteria are
actually surface dwelling. Most of them will be on the
filter floss in your sump. A UV might therefore
increase cycle time by interfering in the bacterial
colonization portion of the cycle. For that reason it
may be best to cycle the system and then turn on the
UV.
Another potential problem is that the UV will do
exactly what it is suppost to do and kill most of the
water born organisms small enough to pass though the
filter. So it may not be easy to keep lifestock that
depends on small waterborn lifeforms as a primary food
source. For example, fan shrimp, mussels, clams, fish
fry.... The UV would kill green water, dyphnia,
larval ghost shrimp, and even fish fry that fit
through the screens on your filter system.
I haven't been following this thread too closely, So I
don't know if you do reef tanks, or if so, what style
of reef keeping you practice. Depending on the style
of reef keeping UV may be ill advised. If you use a
system that is dependent on high microvert diversity
UV would kill the waterborn larval stages and thus
remove part of the food web.
There is also a hypothetical idea floating around that
UV may damage the immune systems of fish by not giving
them enough pratice. This however is a problems for
breeders, as in retail enviroment if you are holding
the fish long enough for it to be a problem, you won't
be in business long enough for it to be a problem.
--- BR0630_at_aol.com wrote:
> In a message dated 1/21/03 5:54:11 AM Mountain
> Standard Time,
> njz_at_clevelandmetroparks.com writes:
>
> > In addition to what Mark has said about trying to
> make a very smooth
> > transition and minimal disease transfer, do some
> checking on the ambient
> > temperature stability in your store. Nothing
> promotes ich more than when
> > there are temperature fluctuations. You may want
> to try to use some data
> > loggers in some of your tanks to see what the
> temps are like throughout the
> > day and night. Obviously smaller tanks would
> fluctuate more rapidly than
> > larger tanks
> >
>
> I've noticed a few fish that were already injured
> when I collected them
> [irrigation ditch nearly dry, with dense
> concentrations of fish - many
> already dead, etc] that since I've kept them in my
> wintering room [40-50F]
> the fungus/ich has decreased on the injury site in
> each fish to the point
> where there is white tissue with no sign of fungus.
> On an unrelated topic,
> has anyone else noticed how, in cold water [40'sF],
> sunfish, bass & crappie
> will hit at food, but frequently have it hit them on
> top of their nose/mouth?
> It's almost like the cold water distorts their
> visual acuity? It happens
> often enough that I'm sure of the direct
> relationship with low temps.
>
> Bruce Scott
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