My apologies for ruffling your feathers: I didn't mean to. Things like "the
germicidal range of killing UV was 265 n
meters with the germicidal effectiveness curve being between 250 n meters
and 280 n meters. Low pressure UV bulbs are in all residential UV devices
and they put out spectral wave length of 254 n meters of radiation, which
is well within the germicidal curve and relatively close to the max peak of
265 n meters." is a little too technical for my understanding - I need
"little words", I guess.

My pond is at saturation for O2 considering the temp: it's heavily aerated
24/7/365. Many people had outbreaks of cyanobacteria/blue-green algae this
year, from Canada to Ireland to England to the Netherlands to Florida and
all points West. Mine was not the problem that other people had, because I
have unrestricted flow to the skimmer (no plants), and enough surface
turbulance from the bubbles to break the nasty little islands when they hit
the surface. But it's there, just the same. As I stated, I *knew* the UV
wouldn't treat it, but I had to try anyway. The UV works perfectly; it just
hasn't been needed this year.

May I ask another question - and not argumentatively? From your
explantation, 92% of the bacteria passing through the light will be killed.
.. . so you mean it will kill things like aeromonas and pseudomonas? That a
UV will, effectively, "sterilize" a pond - short of viruses, at least?

Lee

"Tom La Bron" wrote in message
...
Lee,

Did you read my message? The C&I are at higher wavelength output and they
don't kill even algae. Quote: "C&I units are usually Medium to High
pressure mercury type bulbs and are used for chemical byproducts and waste
water or for the drying of printing inks, lacquers, paints and
adhesives. These units are not effective in germicidal action. The wave
length of the C&I units are in the 320 n and 440 n meter range, which is
well outside of the germicidal effectiveness curve for UV." Unquote.
Medium and high pressure units aren't used in germicidal applications.

As stated before, the following explains, Quote: "In my message on this
subject before I told you that the germicidal range of killing UV was 265
n
meters with the germicidal effectiveness curve being between 250 n meters
and 280 n meters. Low pressure UV bulbs are in all residential UV devices
and they put out spectral wave length of 254 n meters of radiation, which
is well within the germicidal curve and relatively close to the max peak
of
265 n meters. Low pressure UV are
the only effective radiation units for germicidal effectiveness in the
process of disaffection." Unquote.

You say that it kills only algae, and like I stated that if it kills algae
it will virtually 92% of bacteria because that percentage requires less
exposure or less wattage-sec than algae. So if it is killing algae it is
killing bacteria.

I will agree with you that units used for potable water as sterilizers
will
kill everything because it uses mega-wattages, but here again as stated
before these units used by municipalities to sterilize their water are
single pass units, so if it is not killed the first time it doesn't get a
second chance, which a unit in the pond is a recirc unit and it doesn't
have
to worry about it getting missed the first time for it is going to have
another chance at it as the water is recirculated.

As far as flow rate goes that is up the manufacturer, but it does not
limit
you. Red Sea put out an 18w unit that is suppose to handle 1,200gph.
Lifeguard 40watt units are suppose to handle only 1,500gph and yet Aqua UV
40watt units are suppose to handle 2,900gph, but the new Double Helix
36watt
units are suppose to only handle 500gph. According to Aquatic Systems
Inc.
their Smart UV 40watt unit is suppose to be run at 1,574gph for bacteria
and
943gph for algae. Bitron 36watt units are suppose to run at 1,190 gph.
Granted Tetra UV3 is suppose to be able to run at 4,400gph and the Pro
Clear
UV30 is suppose to be able to run at 3,600gph.

It is interesting that you say that you had a cyanobacteria plague, which
a
UV would have a hard time battling any way, because it is usually not
water
borne, so if it is not getting to the UV unit it can't be killed. If the
bacteria is not water borne it will not flow through the UV to be killed.
A
better course of action would have been to flood the pond with lots of air
to increase the oxygen levels because cyanobacteria usually get a hold
when
their is a depletion of oxygen in the environment.

If you don't feel your unit is performing like it should reduce its flow
to
1,500gph and make sure only filtered water is getting to the UV tube.
Like
I said before turbidity of the water can affect the effectiveness of the
unit.

So what unit do you have and have you written the company to voice your
dissatisfaction? Hey if you want to get rid of it, send it to me, I know
it
will work for me because my water is crystal clear.

Tom L.L.


"Lee Brouillet" wrote in message
...
Tom, I'm not trying to dispute anything other than that the normal 15,
20,
or 40 watt UV units sold for ponds are not "sterilizers". The larger
units
sold for home or industrial use for potable water WILL "do the trick",
but
their wattages are considerably higher. And the flow rates are lower. So
there's a longer period of time that the water is exposed to the higher
wattage.

Personally, I haven't had to use my UV this year - so I don't have a
problem
that needs to be dealt with (at least not at this time!). I turned it on
for
3 days earlier this year when I had a cyanobacteria plague, but I knew
in
my
heart that it wouldn't work (and it didn't), so I shut it back down.
However, folks who have sick fish and think that a pond-rated UV will
nuke
the responsible bacteria, or who run a UV and feel "safe" from bacteria,
are
being sold a bill of goods: a UV with a 40 watt bulb and a flow rate of
3200
gph will kill the "green water" algae, but little else.

*That's* the point I was trying to make.

Or am I wrong? If so, I will gladly stand corrected - I'm still learning
every day, and faulty information should be corrected.

Lee


"Tom La Bron" wrote in message
...
OK Folks,

Here go again. You people seem to think that "Commercial and
Industrial"
(C&I) UV's are better than residential units. C&I units are usually
Medium
to High pressure mercury type bulbs and are used for chemical
byproducts
and
waste water or for the drying of printing inks, lacquers, paints and
adhesives. These units are not effective in germicidal action. The
wave
length of the C&I units are in the 320 n and 440 n meter range, which
is
well outside of the germicidal effectiveness curve for UV. Needless
to
say,
the C&I bulbs are not used in residential units, mainly because of
their
expense, plus they are not really any good for germicidal disaffection
and
the amount of heat that they produce in production of their
wavelength.
Also, something else to think about is that C&I units usually only
have
a
lamp-life span of about 1,000 hours, while low-pressure bulbs,
depending
on
the manufacturers have a life span of 2,000 to 9,000 hours.

In my message on this subject before I told you that the germicidal
range
of
killing UV was 265 n meters with the germicidal effectiveness curve
being
between 250 n meters and 280 n meters. Low pressure UV bulbs are in
all
residential UV devices and they put out spectral wave length of 254 n
meters of radiation, which is well within the germicidal curve and
relatively close to the max peak of 265 n meters. Low pressure UV
are
the
only effective radiation units for germicidal effectiveness in the
process
of disaffection. So you are grossly mistaken if you think that C&I
units
are better, because they are not.

Lee, I don't know what you are expecting, but are you filtering your
water
to the 10 micron range before it goes through the UV. As mentioned in
my
previous message Turbidity does effect the UV effectiveness. You
don't
have
to filter to that small, but any thing floating through the water and
through your UV will effect its effectiveness.

Oh, something else, are you a "salter of your pond." Guess what, UV
effectiveness is diminished by salt in the water.

So, I really don't know what your problem is, but it is not your UV,
unless
of course, you are trying to get more mileage out of your bulb that is
recommended by the manufacturer. They are like fluorescent bulbs
which
actually decrease in output the longer they are run. Like I said
before
their lamp-life runs from about 85 days to a little over a year. I am
sure
that if you look at your instructions for your 3-figure unit it will
tell
you its lamp-life.

HTH, clearing things up.

Tom L.L.