The AquaRain Water Filtration System has
been engineered to provide safe drinking water from raw water sources such as rivers,
lakes, streams, creeks, ponds, wells, and cisterns. At the heart of the AquaRain
Water Filtration System are MarathonŽ state-of-the-art ceramic elements utilizing a
long-proven filtration process that is over 100 years old which will safely remove
dangerous waterborne pathogens such as cysts (Cryptospordium, Giardia
bacteria (E. coli, Samonelli typhus, etc...). These innovative MarathonŽ ceramic elements
are also filled with a high grade silvered granulated activated carbon (GAC). The GAC
reduces pesticides, chemicals, chlorine, color, tastes and odors, while leaving the
naturally occurring minerals found in the water unaffected.
The MarathonŽ ceramic elements are carefully
manufactured through a patented extrusion process that results in a very consistent, close
tolerance wall thickness. This allows for accurate measurement of their remaining life and
thereby maintenance of the highest level of reliability and security. Additionally,
Marathon's kilns are compact and operate within very close tolerance temperature ranges.
This provides extremely tight control of the ceramic's final porosity. Every batch of
ceramic elements out of the kilns is tested with mercury porosimetry equipment to confirm
proper pore size distribution. Each finished element is fully flushed at the factory and
is tested twice in the production process to insure complete product integrity.
Traditional ceramics are produced through a
slip-cast method in bulk quantities, utilizing a crude plaster of paris-style mold
process. They are then fired in a high temperature kiln to harden them and open up the
final pore structure. When ceramics are fired in large room-sized kilns, which have a wide
variance in temperatures, the "holes" in the pore structure will vary in size,
resulting in inconsistent product quality. Traditional ceramics therefore cannot achieve
the consistency and reliability of our new patented process extruded ceramics.
One of the most important benefits of the use of
a ceramic produced by the patented MarathonŽ extrusion process, is the consistent,
symmetrical, and measurable wall thickness. This symmetry allows us to externally measure
the remaining wall thickness to determine when the element has reached the end of its
usable life (minimum wall thickness). Determining the minimum safe wall thickness by
independent lab testing and being able to measure that safe minimum on an element in
service, are absolutely critical to having a filtration system you can trust.
Unlike other filters found in the market, our
deep-drawn stainless containers are formed from a single piece of heavy #304 (18-8)
stainless steel and have no welded seams to trap bacteria. The large 3-gallon vessel
allows for more convenient operation with fewer fillings for usable quantities of water. A
new Splash Guard has been added between the upper "raw water" vessel and
the lower filtered drinking water vessel that will deflect spilled water if the upper
container should be overfilled or water splashed over the side. The addition of handles to
the upper vessel facilitates its easy removal, leaving the lower filtered drinking water
container as a more compact, convenient water dispenser.
How Ceramics Work
Ceramic water filters primarily work in two
ways. First, surface sieving, much like a screen door, does not allow larger particles to
pass through the outer surface of the filter. Second, ceramic filters operate as a depth
media, providing a twisting, tortuous path like a maze, trapping contaminants within the
walls (usually in the top .005" below the surface).
Wall thickness is particularly important with
regard to a ceramic's performance as a depth media. The maze-like, tortuous path allows
for filtration performance at an effective pore size that is much less than the actual
median pore diameter of the diatomes from which the filter is made. As clogged filters are
cleaned to restore flow, contaminants in the top .005" of surface material are
removed. Gentle abrasive cleaning will gradually reduce the ceramic wall thickness.
Filtration performance will gradually diminish as wall thickness diminishes. Eventually,
filtration performance will fall below acceptable, safe levels if the filter is used with
walls that have become too thin. This will occur before the filter physically cracks or
breaks, making a reliable end-of-life indicator or gauge absolutely essential for the
health and safety of the user.
The operation of the AquaRain Gravity Water Filter is simplicity itself. First,
collect water for filtration from the cleanest and best possible source. This cold
"raw" water is then poured into the upper container where it trickles down
through the highly specialized ceramic filter elements, leaving cysts, bacteria and
sediment in the outer layer of the ceramic. After passing through the thick ceramic wall,
the water flows through a bed of silvered coconut shell carbon which reduces pesticides,
various chemicals, and chlorine (if present), along with objectionable color, tastes and
odors. The filtered water then drips into the lower storage container where it accumulates
for easy dispensing with our handy NSF-listed lever-action faucet.
Our published water production rates, as well as
with all other gravity water filters on the market, have been established under controlled
and optimum conditions with fully wetted elements. New, dry elements will need several
gallons of water run through them, sometimes 10 or 12, before they are fully wetted and
reach their maximum flow rate. In normal use, water for filtration may be placed in the
upper vessel in the evening and allowed to filter through overnight. In the morning, most
of the water will have filtered through into the lower dispensing container. Additional
water may then be added to the upper container so that a continuous process of filtration
and subsequent use may be established. Keeping the upper vessel as full as possible,
perhaps refilling every fifteen minutes, is essential to reach the maximum production
potential. To halt the production of filtered water, simply lift the upper container and
empty it. The stainless steel lid can then be placed on the bottom container which may be
used as a convenient and compact counter-top water dispenser.
Over time, small particulates and bacteria will
eventually clog the walls of the element and slow the production of water through the
filter. When this occurs, simply remove the filter element(s) and while holding the
threaded end, lightly clean the hard surface of the ceramic with a brush or the scrub pad
provided. The element is then reinstalled in the upper filter vessel, taking care to not
contaminate the clean water end of the elements or the bottom of the upper vessel.
Extensive independent testing is the key to
proving the performance of any water filter product. The Marathon's ceramic filter media,
as used in the AquaRain Gravity Water Filter, has been thoroughly tested by
independent laboratories, government agencies and is currently under testing for NSF
listing. MarathonŽ has also "gone the extra mile" by specifying an especially
difficult testing program that goes far beyond that which is required. Not only have
elements been tested new, as all other manufacturers test, but MarathonŽ also tests
ceramics that have been abraded to their end-of-life tolerance and exposed to raw field
water so that these special test elements approximate true expended parts ready for
disposal, as well as testing elements actually used in a variety field conditions over
their entire life. Testing of these end-of-life elements has demonstrated that the
MarathonŽ ceramic gravity filter elements will remain effective and meet all mandated
performance levels throughout their entire usable life.
MarathonŽ ceramic elements have been
successfully tested in independent laboratories with Cryptosporidium parvum
(kryp-toh-spor-id-dee-um parr-vum) for cyst removal, and with the EPA mandated Klebsiella
terrigena (kleb-see-ell-a terr-ra-gee-na) for bacterial removal. What is particularly
noteworthy, is that the above tests have been passed with fully expended elements, ready
for disposal. The MarathonŽ filter elements have also been successfully tested against
the Health Industry Manufacturing Association's (HIMA) test organism, Brevundimonas
diminuta (bruh-vun-daa-moan-us da-min-u-taa), which is approximately one-third the size of
the EPA bacteria test organism. MarathonŽ has gone the extra mile to insure that our
product will perform as promised and remain effective in producing safe drinking water
throughout its entire life. To the best of our knowledge, no other manufacturer has dared
to test in this way and publish the results of this type of end-of-life testing.
The MarathonŽ filter elements used in the
AquaRain Gravity Water Filter are filled with the highest grade of silvered coconut
shell granulated carbon. The coconut shell carbon has been acid-washed and de-dusted,
making it some of the cleanest carbon available. The silver-carbon is manufactured to meet
NSF 42 requirements for the reduction of pesticides, chemicals, chlorine, color, tastes
AquaRain Gravity Water Filters offer
several unique innovations that set them far ahead of all other gravity water filters:
Patented Extrusion Process: Marathon's patented
extrusion process produces a perfectly formed ceramic "tube" that has exacting
characteristics. The wall dimensions and concentricity are tightly controlled, allowing an
exact external measurement of the remaining wall thickness.
Accurate Kilns: The MarathonŽ elements are
fired in compact computer-controlled kilns which allow complete and accurate control of
the porosity of the finished product. The firing of the ceramic is one of the most
critical steps in the process that determines the final performance of the ceramic filter
element. Bulk firing in large room-size kilns cannot provide the consistency that equals
highly reliable performance in the finished product.
End-Of-Life Gauge For Safety:
The MarathonŽ filter elements incorporate an end-of-life caliper gauge conveniently
snapped onto each element. When this highly accurate gauge can easily slip off of the
ceramic element, the thickness of the ceramic wall has been reduced through cleaning to
the point that we recommend replacing the element. The end-of-life measurement is possible
only because of Marathon's unique patented extrusion process, which produces a consistent
and measurable finished product. Laboratory testing has proven that the MarathonŽ ceramic
element will be safe to use, all the way to the element's measured end-of-life.
Splash Guard: The
AquaRain Gravity Water Filter incorporates a special feature not found on any other
stainless gravity water system. The upper vessel that holds the questionable water has a
stainless steel Splash Guard formed on the bottom of the housing that will deflect
splashed or overfilled water away from the lower storage area holding the filtered water.
Since frequent filling of the upper vessel aids in maximum production, the Splash
Guard adds extra insurance to the daily operation of the AquaRain Gravity
Easy Lift Handles: Two solid stainless steel
handles have been added to the upper housing to allow easy removal for cleaning. The
handles have been spot welded to the container with a special computer operated system
that controls the process precisely, forming a perfect bond.
Simple & Reliable Faucet: The lever-action faucet used on the AquaRain Gravity
Water Filter is very easy to use with a simple push of the lever to draw a cup of clean
water. The lever may also be flipped up to lock it in the open position for high flow
dispensing of larger quantities of water. The simple yet functional design of this
American made, NSF listed faucet, makes it a very reliable part of the AquaRain
Gravity Water Filter. You can depend on it.
Questions and Answers
Q: What is the difference between the Katadyn
and the AquaRain?
A: The Katadyn TRK Gravity Water Filter is a
very good filter and the ceramics are of good quality. The Ceradyn ceramic filter elements
used in the TRK have a separate, less rigid end-of-life gauge similar to ours and their
ceramics are of similar hardness and overall quality. There are several important
differences however. Here are a few...
Our MarathonŽ ceramics have a much smaller pore
size than the Ceradyn and thus a correspondingly higher performance in removing smaller
pathogens. The Ceradyn elements are also filled with a silvered quartz gravel, while our
MarathonŽ elements are filled with a high quality silvered granulated carbon made from
coconut shells that will reduce chlorine and other halogens if present, taste and odors,
color, and some pesticides, chemicals and organic compounds.
The rugged yet attractive AquaRain housing
is constructed of heavy duty 18-8 stainless steel while the Katadyn TRK is made of more
difficult to sanitize plastic.
Lastly, the Katadyn system uses only three
ceramic elements and costs more than our AquaRain Model 400 with four high quality
ceramic elements in a stainless steel housing.
Q: What is the story on "absolute"
A: There is a great deal of confusion regarding
"absolute" micron ratings. Just how much of a reduction efficiency should be
considered adequate for an "absolute" rating? Is 99.9% (3 log) sufficient, or
would 99.9999% (6 log) be more appropriate, since it matches the EPA bacteria requirement?
Should a filter be rated by its ability to remove particles of a certain size, or should
it be challenged with live organisms of a particular size? Should a filter be tested only
when it is new, or should the ratings be based on its end-of-life performance? The fact is
that there is no industry or government standard for "absolute" filtration
The MarathonŽ filter elements used in the
AquaRain Gravity Water Filter have been extensively tested against live organisms
using expended end-of-life elements. We believe this form of testing to be the most
stringent, since it tests the filters in a manner similar to the way they would actually
be used under worst case conditions. When testing against the .5-.6 micron organism
Klebsiella terrigena, EXPENDED MarathonŽ elements demonstrated a 6.6 log reduction (they
achieved 8.9 log reduction when new). The EPA only requires a 6 log reduction from NEW
elements, which we greatly exceeded under extreme pressures of up to 90 psi, well above
normal test pressure. At the very low pressure of ˝ psi found in our gravity filter, the
efficacy would be far greater still. Does this mean that the MarathonŽ filter elements
have an "absolute" rating of only .5-.6 microns? Expended MarathonŽ filter
elements have also been tested against the Health Industry Manufacturing Association's
(HIMA) test organism, Brevundimonas diminuta, and achieved a 99.99815% reduction (99.9999%
when new). Since this organism is .2-.3 micron, should we claim this as our
"absolute" rating? British Berkefeld literature lists the "absolute"
rating of their filter at .9 microns and their U.S. dealers claim "absolute"
performance at .5 microns. Their own factory literature claims only 99.9% efficiency at
the .5 micron level. Is 99.9% sufficient for claiming an "absolute" rating? The
bottom line is that the AquaRain Gravity Water Filter System, using MarathonŽ filter
elements, will outperform all other gravity-fed ceramic water filter systems. Since there
is no standard for "absolute," YOU will have to decide what level of protection
you want for yourself and your family.
Q: How much water will the filter produce?
A: We have established a water production rate
of 25-30 gallons per day for the AquaRain Model 400. This maximum production figure
has been established under controlled and optimum conditions with clean and fully wetted
elements and relatively clear water. Keeping the upper vessel as full as possible, perhaps
refilling every fifteen minutes, is essential to reach the maximum production potential.
In normal daily use, a more conservative production figure of approximately one gallon per
hour would be appropriate for the Model 400 Filter.
Small particulates and bacteria will eventually
clog the walls of the element and slow the production of water through the filter. Proper
cleaning will restore the filter to full flow rates, each and every time.
Q: How long do the filters last?
A: There are two parts to the filter elements;
the ceramic shell, and the granulated carbon filling. Cleaning of the ceramic shell is
what wears out the ceramic portion of the filter. Over time, particulates and bacteria
clog the microscopic pores of the ceramic, slowing down the flow rate. Occasional cleaning
with a small brush or the enclosed green scrub pad will restore the original flow rates.
Our ceramic formulation is very hard and will endure many cleanings, perhaps over 200, if
moderate care is taken and light pressure is used. In normal usage, this equates to
thousands of gallons of water that can be filtered.
The inner carbon filter works by adsorbing
and/or reducing certain chemicals, and has a finite lifetime based on the concentration of
the compounds being reduced. Generally speaking, the carbon capacity should exceed the
life of the ceramic portion of the filter when processing normal chlorinated water. Please
note that when the elements are exhausted from reducing chlorine, that they are still
fully effective for the removal of cysts and bacteria, provided the remaining ceramic wall
thickness still has useful life.
Q: Will the filters remove salt from the water?
A: No. Our ceramic elements leave all of the
naturally occurring minerals intact and will not single out salt alone. This is generally
not a problem with most water sources. If salt is a problem with all of your local water
sources, you can collect rain water and use it to dilute or replace your other sources.
Collected rain water must still be filtered through the AquaRain Filtration System to
insure its safety.
Q: Will the filters remove lead or heavy metals
from the water?
A: No. Generally this is not a concern. Heavy
metal contamination is not commonly found to be a problem in surface waters. Always try to
collect the best water available in clean waterways from a known acceptable source.
While heavy metals reduction is possible, we
believe that when all of the factors are considered, the addition of specialized heavy
metals reduction media will not necessarily be an enhancement to our Water Filtration
System. Special heavy metals reduction media (often ATCTM or ATSTM lead reduction products
from Englehard), will displace volume that could have been used for high quality carbon.
This reduces the overall amount of VOC and chlorine reduction that the filter elements are
capable of achieving. Further, the fine, powdery particle size of heavy metals reduction
media will make the filtration media more dense, thus restricting the flow of water and
slowing output. We feel this is not a good trade-off unless there is a legitimate priority
for heavy metals reduction, as otherwise the reduction media would actually render a
filter LESS effective with these additives.
Q: Will the filters remove nitrates from the
A: No. Nitrates are similar to dissolved
minerals, and ceramics will not remove them. Nitrates, when concentrated, primarily affect
small infants and the aged. Generally, nitrate problems can be avoided with careful water
collection procedures, avoiding areas where livestock gather or where heavy farming with
chemicals is practiced. Use rainwater when in doubt.
Q: How do you clean the ceramic elements?
A: The ceramic elements are very easy to clean.
You simply remove them from the upper container, and while holding the threaded end of the
filter upright, brush lightly downward toward the end cap. Rinse the element after you
have lightly cleaned the surface, taking care that contaminated water does not enter the
hole in the threaded end of the filter. Occasionally it will be necessary to lightly
abrade the surface to restore full flow rate, perhaps after 3 to 5 brush cleanings. If the
inside of the element becomes contaminated during the cleaning process, boil the element
for 5 to 6 minutes (longer when above 4000 foot elevation), allow them to cool, then
reassemble the filter. When reassembling the elements into the upper container, be sure to
keep all exterior surfaces clean and free of contaminated water. Do not allow the lower
filtered water storage container to become contaminated, as disease-causing pathogens may
then be present.
Q: How do you store the filter after use?
A: Simply remove the filter elements and allow
them to completely air dry for at least 24 hours or more. Dry the containers and all parts
and then slide the lower container into the upper container to nest them together. Pack
the elements carefully with padding to avoid breaking them. For maximum protection, we
recommend that you repack the filter system into the original box using the original
packing materials when possible.
Q: Why do the sides of the AquaRain Filter
housings appear magnetic, but the lid and bottoms do not?
A: Our stainless housings are deep-drawn from a
single piece of #304 (18-8) stainless sheet metal. A hydraulic press forms the can shape
into a high powered magnetic form, drawing the stainless down across the iron sides of the
mold. A few very fine particles of magnetized iron will adhere to the walls of the
stainless when the magnetic form separates to remove the housing from the mold. These
particles do not affect the final product in any way whatsoever and will gradually be
cleaned away over time. A single piece deep-drawn housing is always superior to a welded
design, having no welds to alter the stainless formulation or seams to trap bacteria and
Q: How long have AquaRain and MarathonŽ
Ceramics been in business?
A: AquaRain (originally AquaCleer) was
started in 1988, providing advanced water treatment systems designed to meet difficult
treatment challenges in light commercial and residential environments. Development of the
AquaRain Gravity Water Filter began in February of 1998, when we explored methods of
treating water without the use of chemicals, pressure, or man-made energy. We shortly
arrived at the conclusion that ceramics held the promise of meeting our design goals.
AquaRain then began a worldwide search for the best ceramic filter element, ordering
samples and comparing independent test data. MarathonŽ Ceramics was selected as our
manufacturer of choice in July of 1998, and we began working with them to develop the
advanced ceramic filter element that is now used in the AquaRain Gravity Water
MarathonŽ Ceramics was originally formed as a
division of MSR (Mountain Safety Research), Inc. in December 1997, though they had
previously produced ceramics as a department of MSR for internal demand for over two
years. MSR is a subsidiary of REI (Recreation Equipment Inc.), the world's largest
cooperative-owned retailer with over 5 million members.
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