u.v. sterilizer

[lonerider]

I been reading about these uv sterilizers and wondering if anyone runs them
part time. I have a 10,20 and 29 gal. fresh water tanks. I was thinging
about getting a small uv sterilizer lets say 4 watt and a pump. Run it on a
tank for 24 hrs. once a month to kill anything lurking in the water and
clear any algae. Do each tank once a month maype after a partial water
change. Would this be beneficial or just impractical ? Does anyone else do
this ? Are they no good unless run 24 hrs a day 7 days a week? I know for
them to effective they need to placed after a filter. I would just like to
pump water through them unfiltered. I use marineland penquin bio-wheel
filters on all my tanks.
Thanks for your comments,
Larry

[Justin Boucher]

Be careful about the wattage and flow rate. If you intend to use a UV for
periodic sterilization, I would be sure to run it long enough and at low
enough flow rates to ensure irradiation of all protozoa as well as bacteria
and algae. I'm not familiar with the numbers, but perhaps 48 hour runs each
would be better and should you discover any maladies in any of your tanks, I
would go 24/7 until that tank is fully cured of the ailment.

I have a UV running 24/7 on my 240 marine. The tank's too new to give you
any scientific validity, but I use it with the intention of eliminating any
water borne parasites.

Justin

"lonerider" > wrote in message
...
> I been reading about these uv sterilizers and wondering if anyone runs
them
> part time. I have a 10,20 and 29 gal. fresh water tanks. I was thinging
> about getting a small uv sterilizer lets say 4 watt and a pump. Run it on
a
> tank for 24 hrs. once a month to kill anything lurking in the water and
> clear any algae. Do each tank once a month maype after a partial water
> change. Would this be beneficial or just impractical ? Does anyone else do
> this ? Are they no good unless run 24 hrs a day 7 days a week? I know for
> them to effective they need to placed after a filter. I would just like to
> pump water through them unfiltered. I use marineland penquin bio-wheel
> filters on all my tanks.
> Thanks for your comments,
> Larry
>
>

[lonerider]

Hi Justin,
Guess from the no response the freshwater crowd relies on frequent water
changes. Maybe i will leave things alone seeing what i do know works well.
My ol boss had a nice saying "don't poke a skunk"
Thanks,
Larry

"Justin Boucher" > wrote in message
...
> Be careful about the wattage and flow rate. If you intend to use a UV for
> periodic sterilization, I would be sure to run it long enough and at low
> enough flow rates to ensure irradiation of all protozoa as well as
bacteria
> and algae. I'm not familiar with the numbers, but perhaps 48 hour runs
each
> would be better and should you discover any maladies in any of your tanks,
I
> would go 24/7 until that tank is fully cured of the ailment.
>
> I have a UV running 24/7 on my 240 marine. The tank's too new to give you
> any scientific validity, but I use it with the intention of eliminating
any
> water borne parasites.
>
> Justin
>
> "lonerider" > wrote in message
> ...
> > I been reading about these uv sterilizers and wondering if anyone runs
> them
> > part time. I have a 10,20 and 29 gal. fresh water tanks. I was thinging
> > about getting a small uv sterilizer lets say 4 watt and a pump. Run it
on
> a
> > tank for 24 hrs. once a month to kill anything lurking in the water and
> > clear any algae. Do each tank once a month maype after a partial water
> > change. Would this be beneficial or just impractical ? Does anyone else
do
> > this ? Are they no good unless run 24 hrs a day 7 days a week? I know
for
> > them to effective they need to placed after a filter. I would just like
to
> > pump water through them unfiltered. I use marineland penquin bio-wheel
> > filters on all my tanks.
> > Thanks for your comments,
> > Larry
> >
> >
>
>

[Michi Henning]

"lonerider" > wrote in message
...
> I been reading about these uv sterilizers and wondering if anyone runs them
> part time.

If you read the manufacturer's recommendations, they suggest to run
the sterilizer 24x7. The reason is that, this way, you get the best
possible tube life. Switching it on an off speeds up the ageing process
(but I don't know how quickly, sorry). Tube life time also depends
on the type of ballast. Commonly quoted figures are 8,000 hours
with conventional ballast. With an electronic ballast, the same tube
lasts 12,000 hours instead.

> I have a 10,20 and 29 gal. fresh water tanks. I was thinging
> about getting a small uv sterilizer lets say 4 watt and a pump. Run it on a
> tank for 24 hrs. once a month to kill anything lurking in the water and
> clear any algae. Do each tank once a month maype after a partial water
> change. Would this be beneficial or just impractical ? Does anyone else do
> this ? Are they no good unless run 24 hrs a day 7 days a week? I know for
> them to effective they need to placed after a filter. I would just like to
> pump water through them unfiltered. I use marineland penquin bio-wheel
> filters on all my tanks.

You can use a separate power head or pump to get water through the
sterilizer. While that means more hoses cluttering things up, it's also
more convenient: the UV bulb (or the quartz sleeve around the bulb)
should be cleaned every 2-3 months; otherwise, the crud that settles
on the glass inside the sterilizer reduces efficiency. When it comes
to cleaning, it's more convenient to have the sterilizer on a separate pump.
(If you use a separate pump, just have a simple mechanical filter on
the intake side of the sterilizer, to keep out the worst of the crud.)
Of course, you can also plumb the sterilizer into the output path
of your filter, but it makes cleaning or changing the bulb more of
a hassle.

How effective a sterilizer is depends on the zap dosage. Zap dosage
is a measure of the amount of radiation that is delivered. Different
organisms require different zap dosages to die. Zap dosages vary
quite widely. For example, to kill E. Coli, you need a dosage of
6,600 uW/sec/cm2 (microwatts per second per square centimeter),
to kill various yeasts, you need 6,600 to 17,600, to kill protozoans,
you need 22,000 to 200,000, and to kill certain mold spores, you
need as much as 330,000.

So to "kill anything lurking in the water", you'd need very high zap
dosages.

Pragmatically, a zap dosage of 50,000 is reasonable. With that,
you knock over everything but the hardiest of protozoans (Parameium),
and most molds and fungi. To combat green water, you need a minimium
of 22,000 (which is also sufficient to kill most bacteria and yeasts, but
no molds, fungi, or other protozoa).

The zap dosage you get depends on the wattage of the sterilizer and
the rate of flow through the unit. The higher the flow, the shorter the
time the water spends in the sterilizer and is exposed to the radiation;
the stronger the tube, the more water you can move through the
sterilizer per unit of time. (Zap dosage also depends on the length
and the diameter of the tube and the sterilizer housing.)

Finally, you have to consider the total tank volume you want to
service with the sterilizer. That's because, even if your sterilizer
delivers a zap dosage of, say 200,000, there is no point in
having the sterilizer unless you get the entire tank volume through
it quickly enough to knock things on the head before they
reproduce again. In other words, the sterilizer has to have a
throughput that is high enough to outstrip the reproductive rate
of the organisms you want to kill.

To get a well-working system, you should aim to get a high-enough
flow rate to exchange the water in the tank 2 times (or close to it)
per day. If your exchange rate drops below once per day, you are
likely to waste your time. (Note that calculating the exchange rate
is quite complex because the sterilized water, as it returns from
the sterilizer, mixes with the unsterilized water in the tank, so you
the function that describes the ratio of sterilized to unsterilized
water is non-linear. This means that, if you have a 50gal tank,
the exchange rate to exchange the water once per day so that
all (or close to all) of it has passed through the sterilizer is *not*
50/24 gal/h.)

So, lots of variables. To work out what you need, first work
out what flow rate you need. You have a total of 59gal of
tank volume. For that, you get an exchange rate of 1 at 20gal per hour,
and an exchange rate of 2 at 40gal per hour. (These exchange
rates assume that, per factor of one, 99.9% of the water
in your tanks has actually passed through the sterilizer.)

So, aim for a sterilizer that can deliver the zap dosage you want
at 40gal per hour (or at not much below that). If you work
your way through all the math, it turns out that, for a zap dosage
of 50,000, you'll get that (almost exactly) with a 15W sterilizer.

An 8W sterilizer will barely see you through, killing algae
and many bacteria, provided you keep the flow rate at 20gal.
Go below that in flow rate, and you'll get higher zap dosage with
that sterilizer, but you will no longer be turning the tank volume
over quickly enough for the sterilizer to be effective. Go above
that flow rate, and your zap dosage drops below the level where
still kill enough organisms.

So, the short answer to your question is: get an 8W sterilizer,
run it at 20gal per hour, and leave it on 24 hours per day,
and you'll kill green water and most bacteria. Or, better,
get a 15W sterilizer, run it between 30gal and 40gal per
hour, and leave it on 24 hours per day, and you'll kill
most things you would care about in an aquarium. Or
get a 25W sterilizer and run it for something like 10hours
a day at around 50gal/hour, to achieve the same effect,
but more than doubling the standing time of your tube.

Don't bother with anything less than 8W with your size tanks.

If you go ahead and install a sterilizer, take a bucket, time
how long it takes to fill it from the sterilizer output (holding the
sterilizer output at the same height as it will be in the tank), and,
from that, work out the flow rate in gallons per hour. If the flow
rate is too high, install a valve that you can partially close to
get the flow rate low enough to be effective.

Oh, and remember to clean the thing every 2-3 months,
otherwise it will be nothing more than an expensive heater.

Cheers,

Michi.

PS: No, I didn't figure all this out myself. In fact, I figured
out none of it and instead copied it all from
"Aquatic Systems Engineering" by P.R. Escobal. It's
an interesting book, but very dry reading and full of maths.
So, unless you get a kick out of lots of equations, there is
probably no point in reading the book. (Of course, for
people who like this sort of thing, it's another matter ;-)

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com

[lonerider]

Hello Michi,
First of all i really appreciate the time you took for the lenghty reply.
Throughout the years and many many different hobbies i have learned the hard
way several times to keep things simple. Once a hobby becomes too
complicated it turns into a job or chore and is no longer pleasurable and
fun. I have kept a fresh water aquarium set up for about 8 yrs. I went away
for a long week-end to come home to a tank full of dead fish i trusted to
someone to take care of. I emptied the whole thing and stayed away from the
hobby for a few years. Armed this time around with a computer that makes
available tons of knowledge i'm having fun with the research. I started with
a 29gal. christmass gift,then set up the ol trusty 20 gal long and now a 10
gal i found tucked away. I'm really having fun and promised myself to keep
it simple. I'm gonna stick to the bio-wheels,weekly water changes and a few
plants to keep it all healthy.
This group is a wealth of knowledge with a friendly attitude.
Thank You,
Larry

"Michi Henning" > wrote in message
...
> "lonerider" > wrote in message
> ...
> > I been reading about these uv sterilizers and wondering if anyone runs
them
> > part time.
>
> If you read the manufacturer's recommendations, they suggest to run
> the sterilizer 24x7. The reason is that, this way, you get the best
> possible tube life. Switching it on an off speeds up the ageing process
> (but I don't know how quickly, sorry). Tube life time also depends
> on the type of ballast. Commonly quoted figures are 8,000 hours
> with conventional ballast. With an electronic ballast, the same tube
> lasts 12,000 hours instead.
>
> > I have a 10,20 and 29 gal. fresh water tanks. I was thinging
> > about getting a small uv sterilizer lets say 4 watt and a pump. Run it
on a
> > tank for 24 hrs. once a month to kill anything lurking in the water and
> > clear any algae. Do each tank once a month maype after a partial water
> > change. Would this be beneficial or just impractical ? Does anyone else
do
> > this ? Are they no good unless run 24 hrs a day 7 days a week? I know
for
> > them to effective they need to placed after a filter. I would just like
to
> > pump water through them unfiltered. I use marineland penquin bio-wheel
> > filters on all my tanks.
>
> You can use a separate power head or pump to get water through the
> sterilizer. While that means more hoses cluttering things up, it's also
> more convenient: the UV bulb (or the quartz sleeve around the bulb)
> should be cleaned every 2-3 months; otherwise, the crud that settles
> on the glass inside the sterilizer reduces efficiency. When it comes
> to cleaning, it's more convenient to have the sterilizer on a separate
pump.
> (If you use a separate pump, just have a simple mechanical filter on
> the intake side of the sterilizer, to keep out the worst of the crud.)
> Of course, you can also plumb the sterilizer into the output path
> of your filter, but it makes cleaning or changing the bulb more of
> a hassle.
>
> How effective a sterilizer is depends on the zap dosage. Zap dosage
> is a measure of the amount of radiation that is delivered. Different
> organisms require different zap dosages to die. Zap dosages vary
> quite widely. For example, to kill E. Coli, you need a dosage of
> 6,600 uW/sec/cm2 (microwatts per second per square centimeter),
> to kill various yeasts, you need 6,600 to 17,600, to kill protozoans,
> you need 22,000 to 200,000, and to kill certain mold spores, you
> need as much as 330,000.
>
> So to "kill anything lurking in the water", you'd need very high zap
> dosages.
>
> Pragmatically, a zap dosage of 50,000 is reasonable. With that,
> you knock over everything but the hardiest of protozoans (Parameium),
> and most molds and fungi. To combat green water, you need a minimium
> of 22,000 (which is also sufficient to kill most bacteria and yeasts, but
> no molds, fungi, or other protozoa).
>
> The zap dosage you get depends on the wattage of the sterilizer and
> the rate of flow through the unit. The higher the flow, the shorter the
> time the water spends in the sterilizer and is exposed to the radiation;
> the stronger the tube, the more water you can move through the
> sterilizer per unit of time. (Zap dosage also depends on the length
> and the diameter of the tube and the sterilizer housing.)
>
> Finally, you have to consider the total tank volume you want to
> service with the sterilizer. That's because, even if your sterilizer
> delivers a zap dosage of, say 200,000, there is no point in
> having the sterilizer unless you get the entire tank volume through
> it quickly enough to knock things on the head before they
> reproduce again. In other words, the sterilizer has to have a
> throughput that is high enough to outstrip the reproductive rate
> of the organisms you want to kill.
>
> To get a well-working system, you should aim to get a high-enough
> flow rate to exchange the water in the tank 2 times (or close to it)
> per day. If your exchange rate drops below once per day, you are
> likely to waste your time. (Note that calculating the exchange rate
> is quite complex because the sterilized water, as it returns from
> the sterilizer, mixes with the unsterilized water in the tank, so you
> the function that describes the ratio of sterilized to unsterilized
> water is non-linear. This means that, if you have a 50gal tank,
> the exchange rate to exchange the water once per day so that
> all (or close to all) of it has passed through the sterilizer is *not*
> 50/24 gal/h.)
>
> So, lots of variables. To work out what you need, first work
> out what flow rate you need. You have a total of 59gal of
> tank volume. For that, you get an exchange rate of 1 at 20gal per hour,
> and an exchange rate of 2 at 40gal per hour. (These exchange
> rates assume that, per factor of one, 99.9% of the water
> in your tanks has actually passed through the sterilizer.)
>
> So, aim for a sterilizer that can deliver the zap dosage you want
> at 40gal per hour (or at not much below that). If you work
> your way through all the math, it turns out that, for a zap dosage
> of 50,000, you'll get that (almost exactly) with a 15W sterilizer.
>
> An 8W sterilizer will barely see you through, killing algae
> and many bacteria, provided you keep the flow rate at 20gal.
> Go below that in flow rate, and you'll get higher zap dosage with
> that sterilizer, but you will no longer be turning the tank volume
> over quickly enough for the sterilizer to be effective. Go above
> that flow rate, and your zap dosage drops below the level where
> still kill enough organisms.
>
> So, the short answer to your question is: get an 8W sterilizer,
> run it at 20gal per hour, and leave it on 24 hours per day,
> and you'll kill green water and most bacteria. Or, better,
> get a 15W sterilizer, run it between 30gal and 40gal per
> hour, and leave it on 24 hours per day, and you'll kill
> most things you would care about in an aquarium. Or
> get a 25W sterilizer and run it for something like 10hours
> a day at around 50gal/hour, to achieve the same effect,
> but more than doubling the standing time of your tube.
>
> Don't bother with anything less than 8W with your size tanks.
>
> If you go ahead and install a sterilizer, take a bucket, time
> how long it takes to fill it from the sterilizer output (holding the
> sterilizer output at the same height as it will be in the tank), and,
> from that, work out the flow rate in gallons per hour. If the flow
> rate is too high, install a valve that you can partially close to
> get the flow rate low enough to be effective.
>
> Oh, and remember to clean the thing every 2-3 months,
> otherwise it will be nothing more than an expensive heater.
>
> Cheers,
>
> Michi.
>
> PS: No, I didn't figure all this out myself. In fact, I figured
> out none of it and instead copied it all from
> "Aquatic Systems Engineering" by P.R. Escobal. It's
> an interesting book, but very dry reading and full of maths.
> So, unless you get a kick out of lots of equations, there is
> probably no point in reading the book. (Of course, for
> people who like this sort of thing, it's another matter ;-)
>
> --
> Michi Henning Ph: +61 4 1118-2700
> ZeroC, Inc. http://www.zeroc.com
>