Hello all!

I am looking for a bit of advice from you helpful people about what type of
UV steriliser I should buy. Right now I am considering several brands:

Rainbow Lifegard 25watt

Custom Sealife Double Helix
or
Emperor Aquatics 18 watt SMART UV steriliser

I want to lean towards the Rainbow because I can get the spare parts the
easiest, and I can connect it inline without a pump, but I am concerned that
the design of the housing will cause the water to pass mostly under the
bulb.
Thus, wht CS double helix is good for more exposure time, but I am not sure
of it's super-duper polymer sheath instead of the quartz, as well as having
to have a pump connected to it.
The emperor looks solid, but more expensive, and I would have to wait longer
to get it shipped.

Any suggestions or observations about my concerns of each unit??
Thanks!

PS- Going to use it on a 50 Gallon, but want a more powerful one so I can
use it when I get a bigger freshwater tank.

-Seweryn

I prefer the Coralife Turbo Twist. It's easy to connect inline with my
canister - keeps equipment out of the tank. Price is reasonable too.
I've had a double helix in the past, but I like the Turbo Twist better.

"Seweryn" wrote in message
...
Hello all!

I am looking for a bit of advice from you helpful people about what type
of
UV steriliser I should buy. Right now I am considering several brands:

Rainbow Lifegard 25watt

Custom Sealife Double Helix
or
Emperor Aquatics 18 watt SMART UV steriliser

I want to lean towards the Rainbow because I can get the spare parts the
easiest, and I can connect it inline without a pump, but I am concerned
that
the design of the housing will cause the water to pass mostly under the
bulb.
Thus, wht CS double helix is good for more exposure time, but I am not
sure
of it's super-duper polymer sheath instead of the quartz, as well as
having
to have a pump connected to it.
The emperor looks solid, but more expensive, and I would have to wait
longer
to get it shipped.

Any suggestions or observations about my concerns of each unit??
Thanks!

PS- Going to use it on a 50 Gallon, but want a more powerful one so I can
use it when I get a bigger freshwater tank.

-Seweryn

Look for two parameters.

1) First, look for the radius of the cylinder where the water is irradiated.
Three inches is about the best. The reason this is optimal is that it will
give more dwell time for water that is being disinfected without allowing
water to be too far away from the light source. (In a UV sterilizer, water
is pumped into a chamber where it is irradiated. For a fixed pump rate, the
larger this chamber is, the more time the water is going to be exposed to
the UV. On the other hand, the larger is the chamber, the farther some
water can be from the light source during sterilization. One can make a
mathematical argument that the right trade off between these two conflicting
goals (high intensity exposure vs. length of time of exposure) leads to a
radius of about 3 inches. This radius does not change much even when UV
lamps of different wattage are used.

2) Next, buy the highest wattage sterilizer you can. This will give you the
largest feasible operating flow rates for the pump you use to circulate this
water. If you buy too small a lamp, then you can not circulate enough water
through the sterilizer to make tank turnover time small enough. (See
http://www.wideopenwest.com/~brucege...ver/index.html for more
information on turnover time.) If for example you want to control bacteria
and other fast multiplying organisms (such as algae) with a sterilizer, then
you will need to have very fast flow rates with a relatively high wattage
bulb. (Otherwise the algae and bacteria will multiply so faster than your
sterilizer can kill, and the net result will be almost as if you had no
sterilizer at all! This is also provable mathematically.) On the other
hand, if you are after control of protozoa (such as Ick), then slow flow
rates with a high wattage bulb are what you need. (Because protozoa need
higher exposure rates to be affected, but do not multiply nearly as quickly
as bacteria and algae.) Either way, high wattage is better.


I have a custom sealife, and I don't like it, because I do not believe that
the helical water path offers any advantage. Also, I cannot get specific
information on the irradiation levels for the lamp. (I have contacted the
maker several times without success.)

-Bruce Geist


"Seweryn" wrote in message
...
Hello all!

I am looking for a bit of advice from you helpful people about what type
of
UV steriliser I should buy. Right now I am considering several brands:

Rainbow Lifegard 25watt

Custom Sealife Double Helix
or
Emperor Aquatics 18 watt SMART UV steriliser

I want to lean towards the Rainbow because I can get the spare parts the
easiest, and I can connect it inline without a pump, but I am concerned
that
the design of the housing will cause the water to pass mostly under the
bulb.
Thus, wht CS double helix is good for more exposure time, but I am not
sure
of it's super-duper polymer sheath instead of the quartz, as well as
having
to have a pump connected to it.
The emperor looks solid, but more expensive, and I would have to wait
longer
to get it shipped.

Any suggestions or observations about my concerns of each unit??
Thanks!

PS- Going to use it on a 50 Gallon, but want a more powerful one so I can
use it when I get a bigger freshwater tank.

-Seweryn